Merge tag 'i2c-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa...

[linux.git] / drivers / android / binder.c

// SPDX-License-Identifier: GPL-2.0-only
/* binder.c
 *
 * Android IPC Subsystem
 *
 * Copyright (C) 2007-2008 Google, Inc.
 */

/*
 * Locking overview
 *
 * There are 3 main spinlocks which must be acquired in the
 * order shown:
 *
 * 1) proc->outer_lock : protects binder_ref
 *    binder_proc_lock() and binder_proc_unlock() are
 *    used to acq/rel.
 * 2) node->lock : protects most fields of binder_node.
 *    binder_node_lock() and binder_node_unlock() are
 *    used to acq/rel
 * 3) proc->inner_lock : protects the thread and node lists
 *    (proc->threads, proc->waiting_threads, proc->nodes)
 *    and all todo lists associated with the binder_proc
 *    (proc->todo, thread->todo, proc->delivered_death and
 *    node->async_todo), as well as thread->transaction_stack
 *    binder_inner_proc_lock() and binder_inner_proc_unlock()
 *    are used to acq/rel
 *
 * Any lock under procA must never be nested under any lock at the same
 * level or below on procB.
 *
 * Functions that require a lock held on entry indicate which lock
 * in the suffix of the function name:
 *
 * foo_olocked() : requires node->outer_lock
 * foo_nlocked() : requires node->lock
 * foo_ilocked() : requires proc->inner_lock
 * foo_oilocked(): requires proc->outer_lock and proc->inner_lock
 * foo_nilocked(): requires node->lock and proc->inner_lock
 * ...
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nsproxy.h>
#include <linux/poll.h>
#include <linux/debugfs.h>
#include <linux/rbtree.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/pid_namespace.h>
#include <linux/security.h>
#include <linux/spinlock.h>
#include <linux/ratelimit.h>
#include <linux/syscalls.h>
#include <linux/task_work.h>
#include <linux/sizes.h>
#include <linux/ktime.h>

#include <uapi/linux/android/binder.h>

#include <linux/cacheflush.h>

#include "binder_internal.h"
#include "binder_trace.h"

static HLIST_HEAD(binder_deferred_list);
static DEFINE_MUTEX(binder_deferred_lock);

static HLIST_HEAD(binder_devices);
static HLIST_HEAD(binder_procs);
static DEFINE_MUTEX(binder_procs_lock);

static HLIST_HEAD(binder_dead_nodes);
static DEFINE_SPINLOCK(binder_dead_nodes_lock);

static struct dentry *binder_debugfs_dir_entry_root;
static struct dentry *binder_debugfs_dir_entry_proc;
static atomic_t binder_last_id;

static int proc_show(struct seq_file *m, void *unused);
DEFINE_SHOW_ATTRIBUTE(proc);

#define FORBIDDEN_MMAP_FLAGS                (VM_WRITE)

enum {
        BINDER_DEBUG_USER_ERROR             = 1U << 0,
        BINDER_DEBUG_FAILED_TRANSACTION     = 1U << 1,
        BINDER_DEBUG_DEAD_TRANSACTION       = 1U << 2,
        BINDER_DEBUG_OPEN_CLOSE             = 1U << 3,
        BINDER_DEBUG_DEAD_BINDER            = 1U << 4,
        BINDER_DEBUG_DEATH_NOTIFICATION     = 1U << 5,
        BINDER_DEBUG_READ_WRITE             = 1U << 6,
        BINDER_DEBUG_USER_REFS              = 1U << 7,
        BINDER_DEBUG_THREADS                = 1U << 8,
        BINDER_DEBUG_TRANSACTION            = 1U << 9,
        BINDER_DEBUG_TRANSACTION_COMPLETE   = 1U << 10,
        BINDER_DEBUG_FREE_BUFFER            = 1U << 11,
        BINDER_DEBUG_INTERNAL_REFS          = 1U << 12,
        BINDER_DEBUG_PRIORITY_CAP           = 1U << 13,
        BINDER_DEBUG_SPINLOCKS              = 1U << 14,
};
static uint32_t binder_debug_mask = BINDER_DEBUG_USER_ERROR |
        BINDER_DEBUG_FAILED_TRANSACTION | BINDER_DEBUG_DEAD_TRANSACTION;
module_param_named(debug_mask, binder_debug_mask, uint, 0644);

char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
module_param_named(devices, binder_devices_param, charp, 0444);

static DECLARE_WAIT_QUEUE_HEAD(binder_user_error_wait);
static int binder_stop_on_user_error;

static int binder_set_stop_on_user_error(const char *val,
                                         const struct kernel_param *kp)
{
        int ret;

        ret = param_set_int(val, kp);
        if (binder_stop_on_user_error < 2)
                wake_up(&binder_user_error_wait);
        return ret;
}
module_param_call(stop_on_user_error, binder_set_stop_on_user_error,
        param_get_int, &binder_stop_on_user_error, 0644);

static __printf(2, 3) void binder_debug(int mask, const char *format, ...)
{
        struct va_format vaf;
        va_list args;

        if (binder_debug_mask & mask) {
                va_start(args, format);
                vaf.va = &args;
                vaf.fmt = format;
                pr_info_ratelimited("%pV", &vaf);
                va_end(args);
        }
}

#define binder_txn_error(x...) \
        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION, x)

static __printf(1, 2) void binder_user_error(const char *format, ...)
{
        struct va_format vaf;
        va_list args;

        if (binder_debug_mask & BINDER_DEBUG_USER_ERROR) {
                va_start(args, format);
                vaf.va = &args;
                vaf.fmt = format;
                pr_info_ratelimited("%pV", &vaf);
                va_end(args);
        }

        if (binder_stop_on_user_error)
                binder_stop_on_user_error = 2;
}

#define binder_set_extended_error(ee, _id, _command, _param) \
        do { \
                (ee)->id = _id; \
                (ee)->command = _command; \
                (ee)->param = _param; \
        } while (0)

#define to_flat_binder_object(hdr) \
        container_of(hdr, struct flat_binder_object, hdr)

#define to_binder_fd_object(hdr) container_of(hdr, struct binder_fd_object, hdr)

#define to_binder_buffer_object(hdr) \
        container_of(hdr, struct binder_buffer_object, hdr)

#define to_binder_fd_array_object(hdr) \
        container_of(hdr, struct binder_fd_array_object, hdr)

static struct binder_stats binder_stats;

static inline void binder_stats_deleted(enum binder_stat_types type)
{
        atomic_inc(&binder_stats.obj_deleted[type]);
}

static inline void binder_stats_created(enum binder_stat_types type)
{
        atomic_inc(&binder_stats.obj_created[type]);
}

struct binder_transaction_log_entry {
        int debug_id;
        int debug_id_done;
        int call_type;
        int from_proc;
        int from_thread;
        int target_handle;
        int to_proc;
        int to_thread;
        int to_node;
        int data_size;
        int offsets_size;
        int return_error_line;
        uint32_t return_error;
        uint32_t return_error_param;
        char context_name[BINDERFS_MAX_NAME + 1];
};

struct binder_transaction_log {
        atomic_t cur;
        bool full;
        struct binder_transaction_log_entry entry[32];
};

static struct binder_transaction_log binder_transaction_log;
static struct binder_transaction_log binder_transaction_log_failed;

static struct binder_transaction_log_entry *binder_transaction_log_add(
        struct binder_transaction_log *log)
{
        struct binder_transaction_log_entry *e;
        unsigned int cur = atomic_inc_return(&log->cur);

        if (cur >= ARRAY_SIZE(log->entry))
                log->full = true;
        e = &log->entry[cur % ARRAY_SIZE(log->entry)];
        WRITE_ONCE(e->debug_id_done, 0);
        /*
         * write-barrier to synchronize access to e->debug_id_done.
         * We make sure the initialized 0 value is seen before
         * memset() other fields are zeroed by memset.
         */
        smp_wmb();
        memset(e, 0, sizeof(*e));
        return e;
}

enum binder_deferred_state {
        BINDER_DEFERRED_FLUSH        = 0x01,
        BINDER_DEFERRED_RELEASE      = 0x02,
};

enum {
        BINDER_LOOPER_STATE_REGISTERED  = 0x01,
        BINDER_LOOPER_STATE_ENTERED     = 0x02,
        BINDER_LOOPER_STATE_EXITED      = 0x04,
        BINDER_LOOPER_STATE_INVALID     = 0x08,
        BINDER_LOOPER_STATE_WAITING     = 0x10,
        BINDER_LOOPER_STATE_POLL        = 0x20,
};

/**
 * binder_proc_lock() - Acquire outer lock for given binder_proc
 * @proc:         struct binder_proc to acquire
 *
 * Acquires proc->outer_lock. Used to protect binder_ref
 * structures associated with the given proc.
 */
#define binder_proc_lock(proc) _binder_proc_lock(proc, __LINE__)
static void
_binder_proc_lock(struct binder_proc *proc, int line)
        __acquires(&proc->outer_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&proc->outer_lock);
}

/**
 * binder_proc_unlock() - Release outer lock for given binder_proc
 * @proc:                struct binder_proc to acquire
 *
 * Release lock acquired via binder_proc_lock()
 */
#define binder_proc_unlock(proc) _binder_proc_unlock(proc, __LINE__)
static void
_binder_proc_unlock(struct binder_proc *proc, int line)
        __releases(&proc->outer_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_unlock(&proc->outer_lock);
}

/**
 * binder_inner_proc_lock() - Acquire inner lock for given binder_proc
 * @proc:         struct binder_proc to acquire
 *
 * Acquires proc->inner_lock. Used to protect todo lists
 */
#define binder_inner_proc_lock(proc) _binder_inner_proc_lock(proc, __LINE__)
static void
_binder_inner_proc_lock(struct binder_proc *proc, int line)
        __acquires(&proc->inner_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&proc->inner_lock);
}

/**
 * binder_inner_proc_unlock() - Release inner lock for given binder_proc
 * @proc:         struct binder_proc to acquire
 *
 * Release lock acquired via binder_inner_proc_lock()
 */
#define binder_inner_proc_unlock(proc) _binder_inner_proc_unlock(proc, __LINE__)
static void
_binder_inner_proc_unlock(struct binder_proc *proc, int line)
        __releases(&proc->inner_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_unlock(&proc->inner_lock);
}

/**
 * binder_node_lock() - Acquire spinlock for given binder_node
 * @node:         struct binder_node to acquire
 *
 * Acquires node->lock. Used to protect binder_node fields
 */
#define binder_node_lock(node) _binder_node_lock(node, __LINE__)
static void
_binder_node_lock(struct binder_node *node, int line)
        __acquires(&node->lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&node->lock);
}

/**
 * binder_node_unlock() - Release spinlock for given binder_proc
 * @node:         struct binder_node to acquire
 *
 * Release lock acquired via binder_node_lock()
 */
#define binder_node_unlock(node) _binder_node_unlock(node, __LINE__)
static void
_binder_node_unlock(struct binder_node *node, int line)
        __releases(&node->lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_unlock(&node->lock);
}

/**
 * binder_node_inner_lock() - Acquire node and inner locks
 * @node:         struct binder_node to acquire
 *
 * Acquires node->lock. If node->proc also acquires
 * proc->inner_lock. Used to protect binder_node fields
 */
#define binder_node_inner_lock(node) _binder_node_inner_lock(node, __LINE__)
static void
_binder_node_inner_lock(struct binder_node *node, int line)
        __acquires(&node->lock) __acquires(&node->proc->inner_lock)
{
        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        spin_lock(&node->lock);
        if (node->proc)
                binder_inner_proc_lock(node->proc);
        else
                /* annotation for sparse */
                __acquire(&node->proc->inner_lock);
}

/**
 * binder_node_inner_unlock() - Release node and inner locks
 * @node:         struct binder_node to acquire
 *
 * Release lock acquired via binder_node_lock()
 */
#define binder_node_inner_unlock(node) _binder_node_inner_unlock(node, __LINE__)
static void
_binder_node_inner_unlock(struct binder_node *node, int line)
        __releases(&node->lock) __releases(&node->proc->inner_lock)
{
        struct binder_proc *proc = node->proc;

        binder_debug(BINDER_DEBUG_SPINLOCKS,
                     "%s: line=%d\n", __func__, line);
        if (proc)
                binder_inner_proc_unlock(proc);
        else
                /* annotation for sparse */
                __release(&node->proc->inner_lock);
        spin_unlock(&node->lock);
}

static bool binder_worklist_empty_ilocked(struct list_head *list)
{
        return list_empty(list);
}

/**
 * binder_worklist_empty() - Check if no items on the work list
 * @proc:       binder_proc associated with list
 * @list:       list to check
 *
 * Return: true if there are no items on list, else false
 */
static bool binder_worklist_empty(struct binder_proc *proc,
                                  struct list_head *list)
{
        bool ret;

        binder_inner_proc_lock(proc);
        ret = binder_worklist_empty_ilocked(list);
        binder_inner_proc_unlock(proc);
        return ret;
}

/**
 * binder_enqueue_work_ilocked() - Add an item to the work list
 * @work:         struct binder_work to add to list
 * @target_list:  list to add work to
 *
 * Adds the work to the specified list. Asserts that work
 * is not already on a list.
 *
 * Requires the proc->inner_lock to be held.
 */
static void
binder_enqueue_work_ilocked(struct binder_work *work,
                           struct list_head *target_list)
{
        BUG_ON(target_list == NULL);
        BUG_ON(work->entry.next && !list_empty(&work->entry));
        list_add_tail(&work->entry, target_list);
}

/**
 * binder_enqueue_deferred_thread_work_ilocked() - Add deferred thread work
 * @thread:       thread to queue work to
 * @work:         struct binder_work to add to list
 *
 * Adds the work to the todo list of the thread. Doesn't set the process_todo
 * flag, which means that (if it wasn't already set) the thread will go to
 * sleep without handling this work when it calls read.
 *
 * Requires the proc->inner_lock to be held.
 */
static void
binder_enqueue_deferred_thread_work_ilocked(struct binder_thread *thread,
                                            struct binder_work *work)
{
        WARN_ON(!list_empty(&thread->waiting_thread_node));
        binder_enqueue_work_ilocked(work, &thread->todo);
}

/**
 * binder_enqueue_thread_work_ilocked() - Add an item to the thread work list
 * @thread:       thread to queue work to
 * @work:         struct binder_work to add to list
 *
 * Adds the work to the todo list of the thread, and enables processing
 * of the todo queue.
 *
 * Requires the proc->inner_lock to be held.
 */
static void
binder_enqueue_thread_work_ilocked(struct binder_thread *thread,
                                   struct binder_work *work)
{
        WARN_ON(!list_empty(&thread->waiting_thread_node));
        binder_enqueue_work_ilocked(work, &thread->todo);

        /* (e)poll-based threads require an explicit wakeup signal when
         * queuing their own work; they rely on these events to consume
         * messages without I/O block. Without it, threads risk waiting
         * indefinitely without handling the work.
         */
        if (thread->looper & BINDER_LOOPER_STATE_POLL &&
            thread->pid == current->pid && !thread->process_todo)
                wake_up_interruptible_sync(&thread->wait);

        thread->process_todo = true;
}

/**
 * binder_enqueue_thread_work() - Add an item to the thread work list
 * @thread:       thread to queue work to
 * @work:         struct binder_work to add to list
 *
 * Adds the work to the todo list of the thread, and enables processing
 * of the todo queue.
 */
static void
binder_enqueue_thread_work(struct binder_thread *thread,
                           struct binder_work *work)
{
        binder_inner_proc_lock(thread->proc);
        binder_enqueue_thread_work_ilocked(thread, work);
        binder_inner_proc_unlock(thread->proc);
}

static void
binder_dequeue_work_ilocked(struct binder_work *work)
{
        list_del_init(&work->entry);
}

/**
 * binder_dequeue_work() - Removes an item from the work list
 * @proc:         binder_proc associated with list
 * @work:         struct binder_work to remove from list
 *
 * Removes the specified work item from whatever list it is on.
 * Can safely be called if work is not on any list.
 */
static void
binder_dequeue_work(struct binder_proc *proc, struct binder_work *work)
{
        binder_inner_proc_lock(proc);
        binder_dequeue_work_ilocked(work);
        binder_inner_proc_unlock(proc);
}

static struct binder_work *binder_dequeue_work_head_ilocked(
                                        struct list_head *list)
{
        struct binder_work *w;

        w = list_first_entry_or_null(list, struct binder_work, entry);
        if (w)
                list_del_init(&w->entry);
        return w;
}

static void
binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer);
static void binder_free_thread(struct binder_thread *thread);
static void binder_free_proc(struct binder_proc *proc);
static void binder_inc_node_tmpref_ilocked(struct binder_node *node);

static bool binder_has_work_ilocked(struct binder_thread *thread,
                                    bool do_proc_work)
{
        return thread->process_todo ||
                thread->looper_need_return ||
                (do_proc_work &&
                 !binder_worklist_empty_ilocked(&thread->proc->todo));
}

static bool binder_has_work(struct binder_thread *thread, bool do_proc_work)
{
        bool has_work;

        binder_inner_proc_lock(thread->proc);
        has_work = binder_has_work_ilocked(thread, do_proc_work);
        binder_inner_proc_unlock(thread->proc);

        return has_work;
}

static bool binder_available_for_proc_work_ilocked(struct binder_thread *thread)
{
        return !thread->transaction_stack &&
                binder_worklist_empty_ilocked(&thread->todo);
}

static void binder_wakeup_poll_threads_ilocked(struct binder_proc *proc,
                                               bool sync)
{
        struct rb_node *n;
        struct binder_thread *thread;

        for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n)) {
                thread = rb_entry(n, struct binder_thread, rb_node);
                if (thread->looper & BINDER_LOOPER_STATE_POLL &&
                    binder_available_for_proc_work_ilocked(thread)) {
                        if (sync)
                                wake_up_interruptible_sync(&thread->wait);
                        else
                                wake_up_interruptible(&thread->wait);
                }
        }
}

/**
 * binder_select_thread_ilocked() - selects a thread for doing proc work.
 * @proc:       process to select a thread from
 *
 * Note that calling this function moves the thread off the waiting_threads
 * list, so it can only be woken up by the caller of this function, or a
 * signal. Therefore, callers *should* always wake up the thread this function
 * returns.
 *
 * Return:      If there's a thread currently waiting for process work,
 *              returns that thread. Otherwise returns NULL.
 */
static struct binder_thread *
binder_select_thread_ilocked(struct binder_proc *proc)
{
        struct binder_thread *thread;

        assert_spin_locked(&proc->inner_lock);
        thread = list_first_entry_or_null(&proc->waiting_threads,
                                          struct binder_thread,
                                          waiting_thread_node);

        if (thread)
                list_del_init(&thread->waiting_thread_node);

        return thread;
}

/**
 * binder_wakeup_thread_ilocked() - wakes up a thread for doing proc work.
 * @proc:       process to wake up a thread in
 * @thread:     specific thread to wake-up (may be NULL)
 * @sync:       whether to do a synchronous wake-up
 *
 * This function wakes up a thread in the @proc process.
 * The caller may provide a specific thread to wake-up in
 * the @thread parameter. If @thread is NULL, this function
 * will wake up threads that have called poll().
 *
 * Note that for this function to work as expected, callers
 * should first call binder_select_thread() to find a thread
 * to handle the work (if they don't have a thread already),
 * and pass the result into the @thread parameter.
 */
static void binder_wakeup_thread_ilocked(struct binder_proc *proc,
                                         struct binder_thread *thread,
                                         bool sync)
{
        assert_spin_locked(&proc->inner_lock);

        if (thread) {
                if (sync)
                        wake_up_interruptible_sync(&thread->wait);
                else
                        wake_up_interruptible(&thread->wait);
                return;
        }

        /* Didn't find a thread waiting for proc work; this can happen
         * in two scenarios:
         * 1. All threads are busy handling transactions
         *    In that case, one of those threads should call back into
         *    the kernel driver soon and pick up this work.
         * 2. Threads are using the (e)poll interface, in which case
         *    they may be blocked on the waitqueue without having been
         *    added to waiting_threads. For this case, we just iterate
         *    over all threads not handling transaction work, and
         *    wake them all up. We wake all because we don't know whether
         *    a thread that called into (e)poll is handling non-binder
         *    work currently.
         */
        binder_wakeup_poll_threads_ilocked(proc, sync);
}

static void binder_wakeup_proc_ilocked(struct binder_proc *proc)
{
        struct binder_thread *thread = binder_select_thread_ilocked(proc);

        binder_wakeup_thread_ilocked(proc, thread, /* sync = */false);
}

static void binder_set_nice(long nice)
{
        long min_nice;

        if (can_nice(current, nice)) {
                set_user_nice(current, nice);
                return;
        }
        min_nice = rlimit_to_nice(rlimit(RLIMIT_NICE));
        binder_debug(BINDER_DEBUG_PRIORITY_CAP,
                     "%d: nice value %ld not allowed use %ld instead\n",
                      current->pid, nice, min_nice);
        set_user_nice(current, min_nice);
        if (min_nice <= MAX_NICE)
                return;
        binder_user_error("%d RLIMIT_NICE not set\n", current->pid);
}

static struct binder_node *binder_get_node_ilocked(struct binder_proc *proc,
                                                   binder_uintptr_t ptr)
{
        struct rb_node *n = proc->nodes.rb_node;
        struct binder_node *node;

        assert_spin_locked(&proc->inner_lock);

        while (n) {
                node = rb_entry(n, struct binder_node, rb_node);

                if (ptr < node->ptr)
                        n = n->rb_left;
                else if (ptr > node->ptr)
                        n = n->rb_right;
                else {
                        /*
                         * take an implicit weak reference
                         * to ensure node stays alive until
                         * call to binder_put_node()
                         */
                        binder_inc_node_tmpref_ilocked(node);
                        return node;
                }
        }
        return NULL;
}

static struct binder_node *binder_get_node(struct binder_proc *proc,
                                           binder_uintptr_t ptr)
{
        struct binder_node *node;

        binder_inner_proc_lock(proc);
        node = binder_get_node_ilocked(proc, ptr);
        binder_inner_proc_unlock(proc);
        return node;
}

static struct binder_node *binder_init_node_ilocked(
                                                struct binder_proc *proc,
                                                struct binder_node *new_node,
                                                struct flat_binder_object *fp)
{
        struct rb_node **p = &proc->nodes.rb_node;
        struct rb_node *parent = NULL;
        struct binder_node *node;
        binder_uintptr_t ptr = fp ? fp->binder : 0;
        binder_uintptr_t cookie = fp ? fp->cookie : 0;
        __u32 flags = fp ? fp->flags : 0;

        assert_spin_locked(&proc->inner_lock);

        while (*p) {

                parent = *p;
                node = rb_entry(parent, struct binder_node, rb_node);

                if (ptr < node->ptr)
                        p = &(*p)->rb_left;
                else if (ptr > node->ptr)
                        p = &(*p)->rb_right;
                else {
                        /*
                         * A matching node is already in
                         * the rb tree. Abandon the init
                         * and return it.
                         */
                        binder_inc_node_tmpref_ilocked(node);
                        return node;
                }
        }
        node = new_node;
        binder_stats_created(BINDER_STAT_NODE);
        node->tmp_refs++;
        rb_link_node(&node->rb_node, parent, p);
        rb_insert_color(&node->rb_node, &proc->nodes);
        node->debug_id = atomic_inc_return(&binder_last_id);
        node->proc = proc;
        node->ptr = ptr;
        node->cookie = cookie;
        node->work.type = BINDER_WORK_NODE;
        node->min_priority = flags & FLAT_BINDER_FLAG_PRIORITY_MASK;
        node->accept_fds = !!(flags & FLAT_BINDER_FLAG_ACCEPTS_FDS);
        node->txn_security_ctx = !!(flags & FLAT_BINDER_FLAG_TXN_SECURITY_CTX);
        spin_lock_init(&node->lock);
        INIT_LIST_HEAD(&node->work.entry);
        INIT_LIST_HEAD(&node->async_todo);
        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d:%d node %d u%016llx c%016llx created\n",
                     proc->pid, current->pid, node->debug_id,
                     (u64)node->ptr, (u64)node->cookie);

        return node;
}

static struct binder_node *binder_new_node(struct binder_proc *proc,
                                           struct flat_binder_object *fp)
{
        struct binder_node *node;
        struct binder_node *new_node = kzalloc(sizeof(*node), GFP_KERNEL);

        if (!new_node)
                return NULL;
        binder_inner_proc_lock(proc);
        node = binder_init_node_ilocked(proc, new_node, fp);
        binder_inner_proc_unlock(proc);
        if (node != new_node)
                /*
                 * The node was already added by another thread
                 */
                kfree(new_node);

        return node;
}

static void binder_free_node(struct binder_node *node)
{
        kfree(node);
        binder_stats_deleted(BINDER_STAT_NODE);
}

static int binder_inc_node_nilocked(struct binder_node *node, int strong,
                                    int internal,
                                    struct list_head *target_list)
{
        struct binder_proc *proc = node->proc;

        assert_spin_locked(&node->lock);
        if (proc)
                assert_spin_locked(&proc->inner_lock);
        if (strong) {
                if (internal) {
                        if (target_list == NULL &&
                            node->internal_strong_refs == 0 &&
                            !(node->proc &&
                              node == node->proc->context->binder_context_mgr_node &&
                              node->has_strong_ref)) {
                                pr_err("invalid inc strong node for %d\n",
                                        node->debug_id);
                                return -EINVAL;
                        }
                        node->internal_strong_refs++;
                } else
                        node->local_strong_refs++;
                if (!node->has_strong_ref && target_list) {
                        struct binder_thread *thread = container_of(target_list,
                                                    struct binder_thread, todo);
                        binder_dequeue_work_ilocked(&node->work);
                        BUG_ON(&thread->todo != target_list);
                        binder_enqueue_deferred_thread_work_ilocked(thread,
                                                                   &node->work);
                }
        } else {
                if (!internal)
                        node->local_weak_refs++;
                if (!node->has_weak_ref && list_empty(&node->work.entry)) {
                        if (target_list == NULL) {
                                pr_err("invalid inc weak node for %d\n",
                                        node->debug_id);
                                return -EINVAL;
                        }
                        /*
                         * See comment above
                         */
                        binder_enqueue_work_ilocked(&node->work, target_list);
                }
        }
        return 0;
}

static int binder_inc_node(struct binder_node *node, int strong, int internal,
                           struct list_head *target_list)
{
        int ret;

        binder_node_inner_lock(node);
        ret = binder_inc_node_nilocked(node, strong, internal, target_list);
        binder_node_inner_unlock(node);

        return ret;
}

static bool binder_dec_node_nilocked(struct binder_node *node,
                                     int strong, int internal)
{
        struct binder_proc *proc = node->proc;

        assert_spin_locked(&node->lock);
        if (proc)
                assert_spin_locked(&proc->inner_lock);
        if (strong) {
                if (internal)
                        node->internal_strong_refs--;
                else
                        node->local_strong_refs--;
                if (node->local_strong_refs || node->internal_strong_refs)
                        return false;
        } else {
                if (!internal)
                        node->local_weak_refs--;
                if (node->local_weak_refs || node->tmp_refs ||
                                !hlist_empty(&node->refs))
                        return false;
        }

        if (proc && (node->has_strong_ref || node->has_weak_ref)) {
                if (list_empty(&node->work.entry)) {
                        binder_enqueue_work_ilocked(&node->work, &proc->todo);
                        binder_wakeup_proc_ilocked(proc);
                }
        } else {
                if (hlist_empty(&node->refs) && !node->local_strong_refs &&
                    !node->local_weak_refs && !node->tmp_refs) {
                        if (proc) {
                                binder_dequeue_work_ilocked(&node->work);
                                rb_erase(&node->rb_node, &proc->nodes);
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "refless node %d deleted\n",
                                             node->debug_id);
                        } else {
                                BUG_ON(!list_empty(&node->work.entry));
                                spin_lock(&binder_dead_nodes_lock);
                                /*
                                 * tmp_refs could have changed so
                                 * check it again
                                 */
                                if (node->tmp_refs) {
                                        spin_unlock(&binder_dead_nodes_lock);
                                        return false;
                                }
                                hlist_del(&node->dead_node);
                                spin_unlock(&binder_dead_nodes_lock);
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "dead node %d deleted\n",
                                             node->debug_id);
                        }
                        return true;
                }
        }
        return false;
}

static void binder_dec_node(struct binder_node *node, int strong, int internal)
{
        bool free_node;

        binder_node_inner_lock(node);
        free_node = binder_dec_node_nilocked(node, strong, internal);
        binder_node_inner_unlock(node);
        if (free_node)
                binder_free_node(node);
}

static void binder_inc_node_tmpref_ilocked(struct binder_node *node)
{
        /*
         * No call to binder_inc_node() is needed since we
         * don't need to inform userspace of any changes to
         * tmp_refs
         */
        node->tmp_refs++;
}

/**
 * binder_inc_node_tmpref() - take a temporary reference on node
 * @node:       node to reference
 *
 * Take reference on node to prevent the node from being freed
 * while referenced only by a local variable. The inner lock is
 * needed to serialize with the node work on the queue (which
 * isn't needed after the node is dead). If the node is dead
 * (node->proc is NULL), use binder_dead_nodes_lock to protect
 * node->tmp_refs against dead-node-only cases where the node
 * lock cannot be acquired (eg traversing the dead node list to
 * print nodes)
 */
static void binder_inc_node_tmpref(struct binder_node *node)
{
        binder_node_lock(node);
        if (node->proc)
                binder_inner_proc_lock(node->proc);
        else
                spin_lock(&binder_dead_nodes_lock);
        binder_inc_node_tmpref_ilocked(node);
        if (node->proc)
                binder_inner_proc_unlock(node->proc);
        else
                spin_unlock(&binder_dead_nodes_lock);
        binder_node_unlock(node);
}

/**
 * binder_dec_node_tmpref() - remove a temporary reference on node
 * @node:       node to reference
 *
 * Release temporary reference on node taken via binder_inc_node_tmpref()
 */
static void binder_dec_node_tmpref(struct binder_node *node)
{
        bool free_node;

        binder_node_inner_lock(node);
        if (!node->proc)
                spin_lock(&binder_dead_nodes_lock);
        else
                __acquire(&binder_dead_nodes_lock);
        node->tmp_refs--;
        BUG_ON(node->tmp_refs < 0);
        if (!node->proc)
                spin_unlock(&binder_dead_nodes_lock);
        else
                __release(&binder_dead_nodes_lock);
        /*
         * Call binder_dec_node() to check if all refcounts are 0
         * and cleanup is needed. Calling with strong=0 and internal=1
         * causes no actual reference to be released in binder_dec_node().
         * If that changes, a change is needed here too.
         */
        free_node = binder_dec_node_nilocked(node, 0, 1);
        binder_node_inner_unlock(node);
        if (free_node)
                binder_free_node(node);
}

static void binder_put_node(struct binder_node *node)
{
        binder_dec_node_tmpref(node);
}

static struct binder_ref *binder_get_ref_olocked(struct binder_proc *proc,
                                                 u32 desc, bool need_strong_ref)
{
        struct rb_node *n = proc->refs_by_desc.rb_node;
        struct binder_ref *ref;

        while (n) {
                ref = rb_entry(n, struct binder_ref, rb_node_desc);

                if (desc < ref->data.desc) {
                        n = n->rb_left;
                } else if (desc > ref->data.desc) {
                        n = n->rb_right;
                } else if (need_strong_ref && !ref->data.strong) {
                        binder_user_error("tried to use weak ref as strong ref\n");
                        return NULL;
                } else {
                        return ref;
                }
        }
        return NULL;
}

/* Find the smallest unused descriptor the "slow way" */
static u32 slow_desc_lookup_olocked(struct binder_proc *proc, u32 offset)
{
        struct binder_ref *ref;
        struct rb_node *n;
        u32 desc;

        desc = offset;
        for (n = rb_first(&proc->refs_by_desc); n; n = rb_next(n)) {
                ref = rb_entry(n, struct binder_ref, rb_node_desc);
                if (ref->data.desc > desc)
                        break;
                desc = ref->data.desc + 1;
        }

        return desc;
}

/*
 * Find an available reference descriptor ID. The proc->outer_lock might
 * be released in the process, in which case -EAGAIN is returned and the
 * @desc should be considered invalid.
 */
static int get_ref_desc_olocked(struct binder_proc *proc,
                                struct binder_node *node,
                                u32 *desc)
{
        struct dbitmap *dmap = &proc->dmap;
        unsigned int nbits, offset;
        unsigned long *new, bit;

        /* 0 is reserved for the context manager */
        offset = (node == proc->context->binder_context_mgr_node) ? 0 : 1;

        if (!dbitmap_enabled(dmap)) {
                *desc = slow_desc_lookup_olocked(proc, offset);
                return 0;
        }

        if (dbitmap_acquire_next_zero_bit(dmap, offset, &bit) == 0) {
                *desc = bit;
                return 0;
        }

        /*
         * The dbitmap is full and needs to grow. The proc->outer_lock
         * is briefly released to allocate the new bitmap safely.
         */
        nbits = dbitmap_grow_nbits(dmap);
        binder_proc_unlock(proc);
        new = bitmap_zalloc(nbits, GFP_KERNEL);
        binder_proc_lock(proc);
        dbitmap_grow(dmap, new, nbits);

        return -EAGAIN;
}

/**
 * binder_get_ref_for_node_olocked() - get the ref associated with given node
 * @proc:       binder_proc that owns the ref
 * @node:       binder_node of target
 * @new_ref:    newly allocated binder_ref to be initialized or %NULL
 *
 * Look up the ref for the given node and return it if it exists
 *
 * If it doesn't exist and the caller provides a newly allocated
 * ref, initialize the fields of the newly allocated ref and insert
 * into the given proc rb_trees and node refs list.
 *
 * Return:      the ref for node. It is possible that another thread
 *              allocated/initialized the ref first in which case the
 *              returned ref would be different than the passed-in
 *              new_ref. new_ref must be kfree'd by the caller in
 *              this case.
 */
static struct binder_ref *binder_get_ref_for_node_olocked(
                                        struct binder_proc *proc,
                                        struct binder_node *node,
                                        struct binder_ref *new_ref)
{
        struct binder_ref *ref;
        struct rb_node *parent;
        struct rb_node **p;
        u32 desc;

retry:
        p = &proc->refs_by_node.rb_node;
        parent = NULL;
        while (*p) {
                parent = *p;
                ref = rb_entry(parent, struct binder_ref, rb_node_node);

                if (node < ref->node)
                        p = &(*p)->rb_left;
                else if (node > ref->node)
                        p = &(*p)->rb_right;
                else
                        return ref;
        }
        if (!new_ref)
                return NULL;

        /* might release the proc->outer_lock */
        if (get_ref_desc_olocked(proc, node, &desc) == -EAGAIN)
                goto retry;

        binder_stats_created(BINDER_STAT_REF);
        new_ref->data.debug_id = atomic_inc_return(&binder_last_id);
        new_ref->proc = proc;
        new_ref->node = node;
        rb_link_node(&new_ref->rb_node_node, parent, p);
        rb_insert_color(&new_ref->rb_node_node, &proc->refs_by_node);

        new_ref->data.desc = desc;
        p = &proc->refs_by_desc.rb_node;
        while (*p) {
                parent = *p;
                ref = rb_entry(parent, struct binder_ref, rb_node_desc);

                if (new_ref->data.desc < ref->data.desc)
                        p = &(*p)->rb_left;
                else if (new_ref->data.desc > ref->data.desc)
                        p = &(*p)->rb_right;
                else
                        BUG();
        }
        rb_link_node(&new_ref->rb_node_desc, parent, p);
        rb_insert_color(&new_ref->rb_node_desc, &proc->refs_by_desc);

        binder_node_lock(node);
        hlist_add_head(&new_ref->node_entry, &node->refs);

        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d new ref %d desc %d for node %d\n",
                      proc->pid, new_ref->data.debug_id, new_ref->data.desc,
                      node->debug_id);
        binder_node_unlock(node);
        return new_ref;
}

static void binder_cleanup_ref_olocked(struct binder_ref *ref)
{
        struct dbitmap *dmap = &ref->proc->dmap;
        bool delete_node = false;

        binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                     "%d delete ref %d desc %d for node %d\n",
                      ref->proc->pid, ref->data.debug_id, ref->data.desc,
                      ref->node->debug_id);

        if (dbitmap_enabled(dmap))
                dbitmap_clear_bit(dmap, ref->data.desc);
        rb_erase(&ref->rb_node_desc, &ref->proc->refs_by_desc);
        rb_erase(&ref->rb_node_node, &ref->proc->refs_by_node);

        binder_node_inner_lock(ref->node);
        if (ref->data.strong)
                binder_dec_node_nilocked(ref->node, 1, 1);

        hlist_del(&ref->node_entry);
        delete_node = binder_dec_node_nilocked(ref->node, 0, 1);
        binder_node_inner_unlock(ref->node);
        /*
         * Clear ref->node unless we want the caller to free the node
         */
        if (!delete_node) {
                /*
                 * The caller uses ref->node to determine
                 * whether the node needs to be freed. Clear
                 * it since the node is still alive.
                 */
                ref->node = NULL;
        }

        if (ref->death) {
                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                             "%d delete ref %d desc %d has death notification\n",
                              ref->proc->pid, ref->data.debug_id,
                              ref->data.desc);
                binder_dequeue_work(ref->proc, &ref->death->work);
                binder_stats_deleted(BINDER_STAT_DEATH);
        }

        if (ref->freeze) {
                binder_dequeue_work(ref->proc, &ref->freeze->work);
                binder_stats_deleted(BINDER_STAT_FREEZE);
        }

        binder_stats_deleted(BINDER_STAT_REF);
}

/**
 * binder_inc_ref_olocked() - increment the ref for given handle
 * @ref:         ref to be incremented
 * @strong:      if true, strong increment, else weak
 * @target_list: list to queue node work on
 *
 * Increment the ref. @ref->proc->outer_lock must be held on entry
 *
 * Return: 0, if successful, else errno
 */
static int binder_inc_ref_olocked(struct binder_ref *ref, int strong,
                                  struct list_head *target_list)
{
        int ret;

        if (strong) {
                if (ref->data.strong == 0) {
                        ret = binder_inc_node(ref->node, 1, 1, target_list);
                        if (ret)
                                return ret;
                }
                ref->data.strong++;
        } else {
                if (ref->data.weak == 0) {
                        ret = binder_inc_node(ref->node, 0, 1, target_list);
                        if (ret)
                                return ret;
                }
                ref->data.weak++;
        }
        return 0;
}

/**
 * binder_dec_ref_olocked() - dec the ref for given handle
 * @ref:        ref to be decremented
 * @strong:     if true, strong decrement, else weak
 *
 * Decrement the ref.
 *
 * Return: %true if ref is cleaned up and ready to be freed.
 */
static bool binder_dec_ref_olocked(struct binder_ref *ref, int strong)
{
        if (strong) {
                if (ref->data.strong == 0) {
                        binder_user_error("%d invalid dec strong, ref %d desc %d s %d w %d\n",
                                          ref->proc->pid, ref->data.debug_id,
                                          ref->data.desc, ref->data.strong,
                                          ref->data.weak);
                        return false;
                }
                ref->data.strong--;
                if (ref->data.strong == 0)
                        binder_dec_node(ref->node, strong, 1);
        } else {
                if (ref->data.weak == 0) {
                        binder_user_error("%d invalid dec weak, ref %d desc %d s %d w %d\n",
                                          ref->proc->pid, ref->data.debug_id,
                                          ref->data.desc, ref->data.strong,
                                          ref->data.weak);
                        return false;
                }
                ref->data.weak--;
        }
        if (ref->data.strong == 0 && ref->data.weak == 0) {
                binder_cleanup_ref_olocked(ref);
                return true;
        }
        return false;
}

/**
 * binder_get_node_from_ref() - get the node from the given proc/desc
 * @proc:       proc containing the ref
 * @desc:       the handle associated with the ref
 * @need_strong_ref: if true, only return node if ref is strong
 * @rdata:      the id/refcount data for the ref
 *
 * Given a proc and ref handle, return the associated binder_node
 *
 * Return: a binder_node or NULL if not found or not strong when strong required
 */
static struct binder_node *binder_get_node_from_ref(
                struct binder_proc *proc,
                u32 desc, bool need_strong_ref,
                struct binder_ref_data *rdata)
{
        struct binder_node *node;
        struct binder_ref *ref;

        binder_proc_lock(proc);
        ref = binder_get_ref_olocked(proc, desc, need_strong_ref);
        if (!ref)
                goto err_no_ref;
        node = ref->node;
        /*
         * Take an implicit reference on the node to ensure
         * it stays alive until the call to binder_put_node()
         */
        binder_inc_node_tmpref(node);
        if (rdata)
                *rdata = ref->data;
        binder_proc_unlock(proc);

        return node;

err_no_ref:
        binder_proc_unlock(proc);
        return NULL;
}

/**
 * binder_free_ref() - free the binder_ref
 * @ref:        ref to free
 *
 * Free the binder_ref. Free the binder_node indicated by ref->node
 * (if non-NULL) and the binder_ref_death indicated by ref->death.
 */
static void binder_free_ref(struct binder_ref *ref)
{
        if (ref->node)
                binder_free_node(ref->node);
        kfree(ref->death);
        kfree(ref->freeze);
        kfree(ref);
}

/* shrink descriptor bitmap if needed */
static void try_shrink_dmap(struct binder_proc *proc)
{
        unsigned long *new;
        int nbits;

        binder_proc_lock(proc);
        nbits = dbitmap_shrink_nbits(&proc->dmap);
        binder_proc_unlock(proc);

        if (!nbits)
                return;

        new = bitmap_zalloc(nbits, GFP_KERNEL);
        binder_proc_lock(proc);
        dbitmap_shrink(&proc->dmap, new, nbits);
        binder_proc_unlock(proc);
}

/**
 * binder_update_ref_for_handle() - inc/dec the ref for given handle
 * @proc:       proc containing the ref
 * @desc:       the handle associated with the ref
 * @increment:  true=inc reference, false=dec reference
 * @strong:     true=strong reference, false=weak reference
 * @rdata:      the id/refcount data for the ref
 *
 * Given a proc and ref handle, increment or decrement the ref
 * according to "increment" arg.
 *
 * Return: 0 if successful, else errno
 */
static int binder_update_ref_for_handle(struct binder_proc *proc,
                uint32_t desc, bool increment, bool strong,
                struct binder_ref_data *rdata)
{
        int ret = 0;
        struct binder_ref *ref;
        bool delete_ref = false;

        binder_proc_lock(proc);
        ref = binder_get_ref_olocked(proc, desc, strong);
        if (!ref) {
                ret = -EINVAL;
                goto err_no_ref;
        }
        if (increment)
                ret = binder_inc_ref_olocked(ref, strong, NULL);
        else
                delete_ref = binder_dec_ref_olocked(ref, strong);

        if (rdata)
                *rdata = ref->data;
        binder_proc_unlock(proc);

        if (delete_ref) {
                binder_free_ref(ref);
                try_shrink_dmap(proc);
        }
        return ret;

err_no_ref:
        binder_proc_unlock(proc);
        return ret;
}

/**
 * binder_dec_ref_for_handle() - dec the ref for given handle
 * @proc:       proc containing the ref
 * @desc:       the handle associated with the ref
 * @strong:     true=strong reference, false=weak reference
 * @rdata:      the id/refcount data for the ref
 *
 * Just calls binder_update_ref_for_handle() to decrement the ref.
 *
 * Return: 0 if successful, else errno
 */
static int binder_dec_ref_for_handle(struct binder_proc *proc,
                uint32_t desc, bool strong, struct binder_ref_data *rdata)
{
        return binder_update_ref_for_handle(proc, desc, false, strong, rdata);
}


/**
 * binder_inc_ref_for_node() - increment the ref for given proc/node
 * @proc:        proc containing the ref
 * @node:        target node
 * @strong:      true=strong reference, false=weak reference
 * @target_list: worklist to use if node is incremented
 * @rdata:       the id/refcount data for the ref
 *
 * Given a proc and node, increment the ref. Create the ref if it
 * doesn't already exist
 *
 * Return: 0 if successful, else errno
 */
static int binder_inc_ref_for_node(struct binder_proc *proc,
                        struct binder_node *node,
                        bool strong,
                        struct list_head *target_list,
                        struct binder_ref_data *rdata)
{
        struct binder_ref *ref;
        struct binder_ref *new_ref = NULL;
        int ret = 0;

        binder_proc_lock(proc);
        ref = binder_get_ref_for_node_olocked(proc, node, NULL);
        if (!ref) {
                binder_proc_unlock(proc);
                new_ref = kzalloc(sizeof(*ref), GFP_KERNEL);
                if (!new_ref)
                        return -ENOMEM;
                binder_proc_lock(proc);
                ref = binder_get_ref_for_node_olocked(proc, node, new_ref);
        }
        ret = binder_inc_ref_olocked(ref, strong, target_list);
        *rdata = ref->data;
        if (ret && ref == new_ref) {
                /*
                 * Cleanup the failed reference here as the target
                 * could now be dead and have already released its
                 * references by now. Calling on the new reference
                 * with strong=0 and a tmp_refs will not decrement
                 * the node. The new_ref gets kfree'd below.
                 */
                binder_cleanup_ref_olocked(new_ref);
                ref = NULL;
        }

        binder_proc_unlock(proc);
        if (new_ref && ref != new_ref)
                /*
                 * Another thread created the ref first so
                 * free the one we allocated
                 */
                kfree(new_ref);
        return ret;
}

static void binder_pop_transaction_ilocked(struct binder_thread *target_thread,
                                           struct binder_transaction *t)
{
        BUG_ON(!target_thread);
        assert_spin_locked(&target_thread->proc->inner_lock);
        BUG_ON(target_thread->transaction_stack != t);
        BUG_ON(target_thread->transaction_stack->from != target_thread);
        target_thread->transaction_stack =
                target_thread->transaction_stack->from_parent;
        t->from = NULL;
}

/**
 * binder_thread_dec_tmpref() - decrement thread->tmp_ref
 * @thread:     thread to decrement
 *
 * A thread needs to be kept alive while being used to create or
 * handle a transaction. binder_get_txn_from() is used to safely
 * extract t->from from a binder_transaction and keep the thread
 * indicated by t->from from being freed. When done with that
 * binder_thread, this function is called to decrement the
 * tmp_ref and free if appropriate (thread has been released
 * and no transaction being processed by the driver)
 */
static void binder_thread_dec_tmpref(struct binder_thread *thread)
{
        /*
         * atomic is used to protect the counter value while
         * it cannot reach zero or thread->is_dead is false
         */
        binder_inner_proc_lock(thread->proc);
        atomic_dec(&thread->tmp_ref);
        if (thread->is_dead && !atomic_read(&thread->tmp_ref)) {
                binder_inner_proc_unlock(thread->proc);
                binder_free_thread(thread);
                return;
        }
        binder_inner_proc_unlock(thread->proc);
}

/**
 * binder_proc_dec_tmpref() - decrement proc->tmp_ref
 * @proc:       proc to decrement
 *
 * A binder_proc needs to be kept alive while being used to create or
 * handle a transaction. proc->tmp_ref is incremented when
 * creating a new transaction or the binder_proc is currently in-use
 * by threads that are being released. When done with the binder_proc,
 * this function is called to decrement the counter and free the
 * proc if appropriate (proc has been released, all threads have
 * been released and not currently in-use to process a transaction).
 */
static void binder_proc_dec_tmpref(struct binder_proc *proc)
{
        binder_inner_proc_lock(proc);
        proc->tmp_ref--;
        if (proc->is_dead && RB_EMPTY_ROOT(&proc->threads) &&
                        !proc->tmp_ref) {
                binder_inner_proc_unlock(proc);
                binder_free_proc(proc);
                return;
        }
        binder_inner_proc_unlock(proc);
}

/**
 * binder_get_txn_from() - safely extract the "from" thread in transaction
 * @t:  binder transaction for t->from
 *
 * Atomically return the "from" thread and increment the tmp_ref
 * count for the thread to ensure it stays alive until
 * binder_thread_dec_tmpref() is called.
 *
 * Return: the value of t->from
 */
static struct binder_thread *binder_get_txn_from(
                struct binder_transaction *t)
{
        struct binder_thread *from;

        spin_lock(&t->lock);
        from = t->from;
        if (from)
                atomic_inc(&from->tmp_ref);
        spin_unlock(&t->lock);
        return from;
}

/**
 * binder_get_txn_from_and_acq_inner() - get t->from and acquire inner lock
 * @t:  binder transaction for t->from
 *
 * Same as binder_get_txn_from() except it also acquires the proc->inner_lock
 * to guarantee that the thread cannot be released while operating on it.
 * The caller must call binder_inner_proc_unlock() to release the inner lock
 * as well as call binder_dec_thread_txn() to release the reference.
 *
 * Return: the value of t->from
 */
static struct binder_thread *binder_get_txn_from_and_acq_inner(
                struct binder_transaction *t)
        __acquires(&t->from->proc->inner_lock)
{
        struct binder_thread *from;

        from = binder_get_txn_from(t);
        if (!from) {
                __acquire(&from->proc->inner_lock);
                return NULL;
        }
        binder_inner_proc_lock(from->proc);
        if (t->from) {
                BUG_ON(from != t->from);
                return from;
        }
        binder_inner_proc_unlock(from->proc);
        __acquire(&from->proc->inner_lock);
        binder_thread_dec_tmpref(from);
        return NULL;
}

/**
 * binder_free_txn_fixups() - free unprocessed fd fixups
 * @t:  binder transaction for t->from
 *
 * If the transaction is being torn down prior to being
 * processed by the target process, free all of the
 * fd fixups and fput the file structs. It is safe to
 * call this function after the fixups have been
 * processed -- in that case, the list will be empty.
 */
static void binder_free_txn_fixups(struct binder_transaction *t)
{
        struct binder_txn_fd_fixup *fixup, *tmp;

        list_for_each_entry_safe(fixup, tmp, &t->fd_fixups, fixup_entry) {
                fput(fixup->file);
                if (fixup->target_fd >= 0)
                        put_unused_fd(fixup->target_fd);
                list_del(&fixup->fixup_entry);
                kfree(fixup);
        }
}

static void binder_txn_latency_free(struct binder_transaction *t)
{
        int from_proc, from_thread, to_proc, to_thread;

        spin_lock(&t->lock);
        from_proc = t->from ? t->from->proc->pid : 0;
        from_thread = t->from ? t->from->pid : 0;
        to_proc = t->to_proc ? t->to_proc->pid : 0;
        to_thread = t->to_thread ? t->to_thread->pid : 0;
        spin_unlock(&t->lock);

        trace_binder_txn_latency_free(t, from_proc, from_thread, to_proc, to_thread);
}

static void binder_free_transaction(struct binder_transaction *t)
{
        struct binder_proc *target_proc = t->to_proc;

        if (target_proc) {
                binder_inner_proc_lock(target_proc);
                target_proc->outstanding_txns--;
                if (target_proc->outstanding_txns < 0)
                        pr_warn("%s: Unexpected outstanding_txns %d\n",
                                __func__, target_proc->outstanding_txns);
                if (!target_proc->outstanding_txns && target_proc->is_frozen)
                        wake_up_interruptible_all(&target_proc->freeze_wait);
                if (t->buffer)
                        t->buffer->transaction = NULL;
                binder_inner_proc_unlock(target_proc);
        }
        if (trace_binder_txn_latency_free_enabled())
                binder_txn_latency_free(t);
        /*
         * If the transaction has no target_proc, then
         * t->buffer->transaction has already been cleared.
         */
        binder_free_txn_fixups(t);
        kfree(t);
        binder_stats_deleted(BINDER_STAT_TRANSACTION);
}

static void binder_send_failed_reply(struct binder_transaction *t,
                                     uint32_t error_code)
{
        struct binder_thread *target_thread;
        struct binder_transaction *next;

        BUG_ON(t->flags & TF_ONE_WAY);
        while (1) {
                target_thread = binder_get_txn_from_and_acq_inner(t);
                if (target_thread) {
                        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                                     "send failed reply for transaction %d to %d:%d\n",
                                      t->debug_id,
                                      target_thread->proc->pid,
                                      target_thread->pid);

                        binder_pop_transaction_ilocked(target_thread, t);
                        if (target_thread->reply_error.cmd == BR_OK) {
                                target_thread->reply_error.cmd = error_code;
                                binder_enqueue_thread_work_ilocked(
                                        target_thread,
                                        &target_thread->reply_error.work);
                                wake_up_interruptible(&target_thread->wait);
                        } else {
                                /*
                                 * Cannot get here for normal operation, but
                                 * we can if multiple synchronous transactions
                                 * are sent without blocking for responses.
                                 * Just ignore the 2nd error in this case.
                                 */
                                pr_warn("Unexpected reply error: %u\n",
                                        target_thread->reply_error.cmd);
                        }
                        binder_inner_proc_unlock(target_thread->proc);
                        binder_thread_dec_tmpref(target_thread);
                        binder_free_transaction(t);
                        return;
                }
                __release(&target_thread->proc->inner_lock);
                next = t->from_parent;

                binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                             "send failed reply for transaction %d, target dead\n",
                             t->debug_id);

                binder_free_transaction(t);
                if (next == NULL) {
                        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                                     "reply failed, no target thread at root\n");
                        return;
                }
                t = next;
                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                             "reply failed, no target thread -- retry %d\n",
                              t->debug_id);
        }
}

/**
 * binder_cleanup_transaction() - cleans up undelivered transaction
 * @t:          transaction that needs to be cleaned up
 * @reason:     reason the transaction wasn't delivered
 * @error_code: error to return to caller (if synchronous call)
 */
static void binder_cleanup_transaction(struct binder_transaction *t,
                                       const char *reason,
                                       uint32_t error_code)
{
        if (t->buffer->target_node && !(t->flags & TF_ONE_WAY)) {
                binder_send_failed_reply(t, error_code);
        } else {
                binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                        "undelivered transaction %d, %s\n",
                        t->debug_id, reason);
                binder_free_transaction(t);
        }
}

/**
 * binder_get_object() - gets object and checks for valid metadata
 * @proc:       binder_proc owning the buffer
 * @u:          sender's user pointer to base of buffer
 * @buffer:     binder_buffer that we're parsing.
 * @offset:     offset in the @buffer at which to validate an object.
 * @object:     struct binder_object to read into
 *
 * Copy the binder object at the given offset into @object. If @u is
 * provided then the copy is from the sender's buffer. If not, then
 * it is copied from the target's @buffer.
 *
 * Return:      If there's a valid metadata object at @offset, the
 *              size of that object. Otherwise, it returns zero. The object
 *              is read into the struct binder_object pointed to by @object.
 */
static size_t binder_get_object(struct binder_proc *proc,
                                const void __user *u,
                                struct binder_buffer *buffer,
                                unsigned long offset,
                                struct binder_object *object)
{
        size_t read_size;
        struct binder_object_header *hdr;
        size_t object_size = 0;

        read_size = min_t(size_t, sizeof(*object), buffer->data_size - offset);
        if (offset > buffer->data_size || read_size < sizeof(*hdr) ||
            !IS_ALIGNED(offset, sizeof(u32)))
                return 0;

        if (u) {
                if (copy_from_user(object, u + offset, read_size))
                        return 0;
        } else {
                if (binder_alloc_copy_from_buffer(&proc->alloc, object, buffer,
                                                  offset, read_size))
                        return 0;
        }

        /* Ok, now see if we read a complete object. */
        hdr = &object->hdr;
        switch (hdr->type) {
        case BINDER_TYPE_BINDER:
        case BINDER_TYPE_WEAK_BINDER:
        case BINDER_TYPE_HANDLE:
        case BINDER_TYPE_WEAK_HANDLE:
                object_size = sizeof(struct flat_binder_object);
                break;
        case BINDER_TYPE_FD:
                object_size = sizeof(struct binder_fd_object);
                break;
        case BINDER_TYPE_PTR:
                object_size = sizeof(struct binder_buffer_object);
                break;
        case BINDER_TYPE_FDA:
                object_size = sizeof(struct binder_fd_array_object);
                break;
        default:
                return 0;
        }
        if (offset <= buffer->data_size - object_size &&
            buffer->data_size >= object_size)
                return object_size;
        else
                return 0;
}

/**
 * binder_validate_ptr() - validates binder_buffer_object in a binder_buffer.
 * @proc:       binder_proc owning the buffer
 * @b:          binder_buffer containing the object
 * @object:     struct binder_object to read into
 * @index:      index in offset array at which the binder_buffer_object is
 *              located
 * @start_offset: points to the start of the offset array
 * @object_offsetp: offset of @object read from @b
 * @num_valid:  the number of valid offsets in the offset array
 *
 * Return:      If @index is within the valid range of the offset array
 *              described by @start and @num_valid, and if there's a valid
 *              binder_buffer_object at the offset found in index @index
 *              of the offset array, that object is returned. Otherwise,
 *              %NULL is returned.
 *              Note that the offset found in index @index itself is not
 *              verified; this function assumes that @num_valid elements
 *              from @start were previously verified to have valid offsets.
 *              If @object_offsetp is non-NULL, then the offset within
 *              @b is written to it.
 */
static struct binder_buffer_object *binder_validate_ptr(
                                                struct binder_proc *proc,
                                                struct binder_buffer *b,
                                                struct binder_object *object,
                                                binder_size_t index,
                                                binder_size_t start_offset,
                                                binder_size_t *object_offsetp,
                                                binder_size_t num_valid)
{
        size_t object_size;
        binder_size_t object_offset;
        unsigned long buffer_offset;

        if (index >= num_valid)
                return NULL;

        buffer_offset = start_offset + sizeof(binder_size_t) * index;
        if (binder_alloc_copy_from_buffer(&proc->alloc, &object_offset,
                                          b, buffer_offset,
                                          sizeof(object_offset)))
                return NULL;
        object_size = binder_get_object(proc, NULL, b, object_offset, object);
        if (!object_size || object->hdr.type != BINDER_TYPE_PTR)
                return NULL;
        if (object_offsetp)
                *object_offsetp = object_offset;

        return &object->bbo;
}

/**
 * binder_validate_fixup() - validates pointer/fd fixups happen in order.
 * @proc:               binder_proc owning the buffer
 * @b:                  transaction buffer
 * @objects_start_offset: offset to start of objects buffer
 * @buffer_obj_offset:  offset to binder_buffer_object in which to fix up
 * @fixup_offset:       start offset in @buffer to fix up
 * @last_obj_offset:    offset to last binder_buffer_object that we fixed
 * @last_min_offset:    minimum fixup offset in object at @last_obj_offset
 *
 * Return:              %true if a fixup in buffer @buffer at offset @offset is
 *                      allowed.
 *
 * For safety reasons, we only allow fixups inside a buffer to happen
 * at increasing offsets; additionally, we only allow fixup on the last
 * buffer object that was verified, or one of its parents.
 *
 * Example of what is allowed:
 *
 * A
 *   B (parent = A, offset = 0)
 *   C (parent = A, offset = 16)
 *     D (parent = C, offset = 0)
 *   E (parent = A, offset = 32) // min_offset is 16 (C.parent_offset)
 *
 * Examples of what is not allowed:
 *
 * Decreasing offsets within the same parent:
 * A
 *   C (parent = A, offset = 16)
 *   B (parent = A, offset = 0) // decreasing offset within A
 *
 * Referring to a parent that wasn't the last object or any of its parents:
 * A
 *   B (parent = A, offset = 0)
 *   C (parent = A, offset = 0)
 *   C (parent = A, offset = 16)
 *     D (parent = B, offset = 0) // B is not A or any of A's parents
 */
static bool binder_validate_fixup(struct binder_proc *proc,
                                  struct binder_buffer *b,
                                  binder_size_t objects_start_offset,
                                  binder_size_t buffer_obj_offset,
                                  binder_size_t fixup_offset,
                                  binder_size_t last_obj_offset,
                                  binder_size_t last_min_offset)
{
        if (!last_obj_offset) {
                /* Nothing to fix up in */
                return false;
        }

        while (last_obj_offset != buffer_obj_offset) {
                unsigned long buffer_offset;
                struct binder_object last_object;
                struct binder_buffer_object *last_bbo;
                size_t object_size = binder_get_object(proc, NULL, b,
                                                       last_obj_offset,
                                                       &last_object);
                if (object_size != sizeof(*last_bbo))
                        return false;

                last_bbo = &last_object.bbo;
                /*
                 * Safe to retrieve the parent of last_obj, since it
                 * was already previously verified by the driver.
                 */
                if ((last_bbo->flags & BINDER_BUFFER_FLAG_HAS_PARENT) == 0)
                        return false;
                last_min_offset = last_bbo->parent_offset + sizeof(uintptr_t);
                buffer_offset = objects_start_offset +
                        sizeof(binder_size_t) * last_bbo->parent;
                if (binder_alloc_copy_from_buffer(&proc->alloc,
                                                  &last_obj_offset,
                                                  b, buffer_offset,
                                                  sizeof(last_obj_offset)))
                        return false;
        }
        return (fixup_offset >= last_min_offset);
}

/**
 * struct binder_task_work_cb - for deferred close
 *
 * @twork:                callback_head for task work
 * @fd:                   fd to close
 *
 * Structure to pass task work to be handled after
 * returning from binder_ioctl() via task_work_add().
 */
struct binder_task_work_cb {
        struct callback_head twork;
        struct file *file;
};

/**
 * binder_do_fd_close() - close list of file descriptors
 * @twork:      callback head for task work
 *
 * It is not safe to call ksys_close() during the binder_ioctl()
 * function if there is a chance that binder's own file descriptor
 * might be closed. This is to meet the requirements for using
 * fdget() (see comments for __fget_light()). Therefore use
 * task_work_add() to schedule the close operation once we have
 * returned from binder_ioctl(). This function is a callback
 * for that mechanism and does the actual ksys_close() on the
 * given file descriptor.
 */
static void binder_do_fd_close(struct callback_head *twork)
{
        struct binder_task_work_cb *twcb = container_of(twork,
                        struct binder_task_work_cb, twork);

        fput(twcb->file);
        kfree(twcb);
}

/**
 * binder_deferred_fd_close() - schedule a close for the given file-descriptor
 * @fd:         file-descriptor to close
 *
 * See comments in binder_do_fd_close(). This function is used to schedule
 * a file-descriptor to be closed after returning from binder_ioctl().
 */
static void binder_deferred_fd_close(int fd)
{
        struct binder_task_work_cb *twcb;

        twcb = kzalloc(sizeof(*twcb), GFP_KERNEL);
        if (!twcb)
                return;
        init_task_work(&twcb->twork, binder_do_fd_close);
        twcb->file = file_close_fd(fd);
        if (twcb->file) {
                // pin it until binder_do_fd_close(); see comments there
                get_file(twcb->file);
                filp_close(twcb->file, current->files);
                task_work_add(current, &twcb->twork, TWA_RESUME);
        } else {
                kfree(twcb);
        }
}

static void binder_transaction_buffer_release(struct binder_proc *proc,
                                              struct binder_thread *thread,
                                              struct binder_buffer *buffer,
                                              binder_size_t off_end_offset,
                                              bool is_failure)
{
        int debug_id = buffer->debug_id;
        binder_size_t off_start_offset, buffer_offset;

        binder_debug(BINDER_DEBUG_TRANSACTION,
                     "%d buffer release %d, size %zd-%zd, failed at %llx\n",
                     proc->pid, buffer->debug_id,
                     buffer->data_size, buffer->offsets_size,
                     (unsigned long long)off_end_offset);

        if (buffer->target_node)
                binder_dec_node(buffer->target_node, 1, 0);

        off_start_offset = ALIGN(buffer->data_size, sizeof(void *));

        for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
             buffer_offset += sizeof(binder_size_t)) {
                struct binder_object_header *hdr;
                size_t object_size = 0;
                struct binder_object object;
                binder_size_t object_offset;

                if (!binder_alloc_copy_from_buffer(&proc->alloc, &object_offset,
                                                   buffer, buffer_offset,
                                                   sizeof(object_offset)))
                        object_size = binder_get_object(proc, NULL, buffer,
                                                        object_offset, &object);
                if (object_size == 0) {
                        pr_err("transaction release %d bad object at offset %lld, size %zd\n",
                               debug_id, (u64)object_offset, buffer->data_size);
                        continue;
                }
                hdr = &object.hdr;
                switch (hdr->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {
                        struct flat_binder_object *fp;
                        struct binder_node *node;

                        fp = to_flat_binder_object(hdr);
                        node = binder_get_node(proc, fp->binder);
                        if (node == NULL) {
                                pr_err("transaction release %d bad node %016llx\n",
                                       debug_id, (u64)fp->binder);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        node %d u%016llx\n",
                                     node->debug_id, (u64)node->ptr);
                        binder_dec_node(node, hdr->type == BINDER_TYPE_BINDER,
                                        0);
                        binder_put_node(node);
                } break;
                case BINDER_TYPE_HANDLE:
                case BINDER_TYPE_WEAK_HANDLE: {
                        struct flat_binder_object *fp;
                        struct binder_ref_data rdata;
                        int ret;

                        fp = to_flat_binder_object(hdr);
                        ret = binder_dec_ref_for_handle(proc, fp->handle,
                                hdr->type == BINDER_TYPE_HANDLE, &rdata);

                        if (ret) {
                                pr_err("transaction release %d bad handle %d, ret = %d\n",
                                 debug_id, fp->handle, ret);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "        ref %d desc %d\n",
                                     rdata.debug_id, rdata.desc);
                } break;

                case BINDER_TYPE_FD: {
                        /*
                         * No need to close the file here since user-space
                         * closes it for successfully delivered
                         * transactions. For transactions that weren't
                         * delivered, the new fd was never allocated so
                         * there is no need to close and the fput on the
                         * file is done when the transaction is torn
                         * down.
                         */
                } break;
                case BINDER_TYPE_PTR:
                        /*
                         * Nothing to do here, this will get cleaned up when the
                         * transaction buffer gets freed
                         */
                        break;
                case BINDER_TYPE_FDA: {
                        struct binder_fd_array_object *fda;
                        struct binder_buffer_object *parent;
                        struct binder_object ptr_object;
                        binder_size_t fda_offset;
                        size_t fd_index;
                        binder_size_t fd_buf_size;
                        binder_size_t num_valid;

                        if (is_failure) {
                                /*
                                 * The fd fixups have not been applied so no
                                 * fds need to be closed.
                                 */
                                continue;
                        }

                        num_valid = (buffer_offset - off_start_offset) /
                                                sizeof(binder_size_t);
                        fda = to_binder_fd_array_object(hdr);
                        parent = binder_validate_ptr(proc, buffer, &ptr_object,
                                                     fda->parent,
                                                     off_start_offset,
                                                     NULL,
                                                     num_valid);
                        if (!parent) {
                                pr_err("transaction release %d bad parent offset\n",
                                       debug_id);
                                continue;
                        }
                        fd_buf_size = sizeof(u32) * fda->num_fds;
                        if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
                                pr_err("transaction release %d invalid number of fds (%lld)\n",
                                       debug_id, (u64)fda->num_fds);
                                continue;
                        }
                        if (fd_buf_size > parent->length ||
                            fda->parent_offset > parent->length - fd_buf_size) {
                                /* No space for all file descriptors here. */
                                pr_err("transaction release %d not enough space for %lld fds in buffer\n",
                                       debug_id, (u64)fda->num_fds);
                                continue;
                        }
                        /*
                         * the source data for binder_buffer_object is visible
                         * to user-space and the @buffer element is the user
                         * pointer to the buffer_object containing the fd_array.
                         * Convert the address to an offset relative to
                         * the base of the transaction buffer.
                         */
                        fda_offset = parent->buffer - buffer->user_data +
                                fda->parent_offset;
                        for (fd_index = 0; fd_index < fda->num_fds;
                             fd_index++) {
                                u32 fd;
                                int err;
                                binder_size_t offset = fda_offset +
                                        fd_index * sizeof(fd);

                                err = binder_alloc_copy_from_buffer(
                                                &proc->alloc, &fd, buffer,
                                                offset, sizeof(fd));
                                WARN_ON(err);
                                if (!err) {
                                        binder_deferred_fd_close(fd);
                                        /*
                                         * Need to make sure the thread goes
                                         * back to userspace to complete the
                                         * deferred close
                                         */
                                        if (thread)
                                                thread->looper_need_return = true;
                                }
                        }
                } break;
                default:
                        pr_err("transaction release %d bad object type %x\n",
                                debug_id, hdr->type);
                        break;
                }
        }
}

/* Clean up all the objects in the buffer */
static inline void binder_release_entire_buffer(struct binder_proc *proc,
                                                struct binder_thread *thread,
                                                struct binder_buffer *buffer,
                                                bool is_failure)
{
        binder_size_t off_end_offset;

        off_end_offset = ALIGN(buffer->data_size, sizeof(void *));
        off_end_offset += buffer->offsets_size;

        binder_transaction_buffer_release(proc, thread, buffer,
                                          off_end_offset, is_failure);
}

static int binder_translate_binder(struct flat_binder_object *fp,
                                   struct binder_transaction *t,
                                   struct binder_thread *thread)
{
        struct binder_node *node;
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_ref_data rdata;
        int ret = 0;

        node = binder_get_node(proc, fp->binder);
        if (!node) {
                node = binder_new_node(proc, fp);
                if (!node)
                        return -ENOMEM;
        }
        if (fp->cookie != node->cookie) {
                binder_user_error("%d:%d sending u%016llx node %d, cookie mismatch %016llx != %016llx\n",
                                  proc->pid, thread->pid, (u64)fp->binder,
                                  node->debug_id, (u64)fp->cookie,
                                  (u64)node->cookie);
                ret = -EINVAL;
                goto done;
        }
        if (security_binder_transfer_binder(proc->cred, target_proc->cred)) {
                ret = -EPERM;
                goto done;
        }

        ret = binder_inc_ref_for_node(target_proc, node,
                        fp->hdr.type == BINDER_TYPE_BINDER,
                        &thread->todo, &rdata);
        if (ret)
                goto done;

        if (fp->hdr.type == BINDER_TYPE_BINDER)
                fp->hdr.type = BINDER_TYPE_HANDLE;
        else
                fp->hdr.type = BINDER_TYPE_WEAK_HANDLE;
        fp->binder = 0;
        fp->handle = rdata.desc;
        fp->cookie = 0;

        trace_binder_transaction_node_to_ref(t, node, &rdata);
        binder_debug(BINDER_DEBUG_TRANSACTION,
                     "        node %d u%016llx -> ref %d desc %d\n",
                     node->debug_id, (u64)node->ptr,
                     rdata.debug_id, rdata.desc);
done:
        binder_put_node(node);
        return ret;
}

static int binder_translate_handle(struct flat_binder_object *fp,
                                   struct binder_transaction *t,
                                   struct binder_thread *thread)
{
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_node *node;
        struct binder_ref_data src_rdata;
        int ret = 0;

        node = binder_get_node_from_ref(proc, fp->handle,
                        fp->hdr.type == BINDER_TYPE_HANDLE, &src_rdata);
        if (!node) {
                binder_user_error("%d:%d got transaction with invalid handle, %d\n",
                                  proc->pid, thread->pid, fp->handle);
                return -EINVAL;
        }
        if (security_binder_transfer_binder(proc->cred, target_proc->cred)) {
                ret = -EPERM;
                goto done;
        }

        binder_node_lock(node);
        if (node->proc == target_proc) {
                if (fp->hdr.type == BINDER_TYPE_HANDLE)
                        fp->hdr.type = BINDER_TYPE_BINDER;
                else
                        fp->hdr.type = BINDER_TYPE_WEAK_BINDER;
                fp->binder = node->ptr;
                fp->cookie = node->cookie;
                if (node->proc)
                        binder_inner_proc_lock(node->proc);
                else
                        __acquire(&node->proc->inner_lock);
                binder_inc_node_nilocked(node,
                                         fp->hdr.type == BINDER_TYPE_BINDER,
                                         0, NULL);
                if (node->proc)
                        binder_inner_proc_unlock(node->proc);
                else
                        __release(&node->proc->inner_lock);
                trace_binder_transaction_ref_to_node(t, node, &src_rdata);
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "        ref %d desc %d -> node %d u%016llx\n",
                             src_rdata.debug_id, src_rdata.desc, node->debug_id,
                             (u64)node->ptr);
                binder_node_unlock(node);
        } else {
                struct binder_ref_data dest_rdata;

                binder_node_unlock(node);
                ret = binder_inc_ref_for_node(target_proc, node,
                                fp->hdr.type == BINDER_TYPE_HANDLE,
                                NULL, &dest_rdata);
                if (ret)
                        goto done;

                fp->binder = 0;
                fp->handle = dest_rdata.desc;
                fp->cookie = 0;
                trace_binder_transaction_ref_to_ref(t, node, &src_rdata,
                                                    &dest_rdata);
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "        ref %d desc %d -> ref %d desc %d (node %d)\n",
                             src_rdata.debug_id, src_rdata.desc,
                             dest_rdata.debug_id, dest_rdata.desc,
                             node->debug_id);
        }
done:
        binder_put_node(node);
        return ret;
}

static int binder_translate_fd(u32 fd, binder_size_t fd_offset,
                               struct binder_transaction *t,
                               struct binder_thread *thread,
                               struct binder_transaction *in_reply_to)
{
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_txn_fd_fixup *fixup;
        struct file *file;
        int ret = 0;
        bool target_allows_fd;

        if (in_reply_to)
                target_allows_fd = !!(in_reply_to->flags & TF_ACCEPT_FDS);
        else
                target_allows_fd = t->buffer->target_node->accept_fds;
        if (!target_allows_fd) {
                binder_user_error("%d:%d got %s with fd, %d, but target does not allow fds\n",
                                  proc->pid, thread->pid,
                                  in_reply_to ? "reply" : "transaction",
                                  fd);
                ret = -EPERM;
                goto err_fd_not_accepted;
        }

        file = fget(fd);
        if (!file) {
                binder_user_error("%d:%d got transaction with invalid fd, %d\n",
                                  proc->pid, thread->pid, fd);
                ret = -EBADF;
                goto err_fget;
        }
        ret = security_binder_transfer_file(proc->cred, target_proc->cred, file);
        if (ret < 0) {
                ret = -EPERM;
                goto err_security;
        }

        /*
         * Add fixup record for this transaction. The allocation
         * of the fd in the target needs to be done from a
         * target thread.
         */
        fixup = kzalloc(sizeof(*fixup), GFP_KERNEL);
        if (!fixup) {
                ret = -ENOMEM;
                goto err_alloc;
        }
        fixup->file = file;
        fixup->offset = fd_offset;
        fixup->target_fd = -1;
        trace_binder_transaction_fd_send(t, fd, fixup->offset);
        list_add_tail(&fixup->fixup_entry, &t->fd_fixups);

        return ret;

err_alloc:
err_security:
        fput(file);
err_fget:
err_fd_not_accepted:
        return ret;
}

/**
 * struct binder_ptr_fixup - data to be fixed-up in target buffer
 * @offset      offset in target buffer to fixup
 * @skip_size   bytes to skip in copy (fixup will be written later)
 * @fixup_data  data to write at fixup offset
 * @node        list node
 *
 * This is used for the pointer fixup list (pf) which is created and consumed
 * during binder_transaction() and is only accessed locally. No
 * locking is necessary.
 *
 * The list is ordered by @offset.
 */
struct binder_ptr_fixup {
        binder_size_t offset;
        size_t skip_size;
        binder_uintptr_t fixup_data;
        struct list_head node;
};

/**
 * struct binder_sg_copy - scatter-gather data to be copied
 * @offset              offset in target buffer
 * @sender_uaddr        user address in source buffer
 * @length              bytes to copy
 * @node                list node
 *
 * This is used for the sg copy list (sgc) which is created and consumed
 * during binder_transaction() and is only accessed locally. No
 * locking is necessary.
 *
 * The list is ordered by @offset.
 */
struct binder_sg_copy {
        binder_size_t offset;
        const void __user *sender_uaddr;
        size_t length;
        struct list_head node;
};

/**
 * binder_do_deferred_txn_copies() - copy and fixup scatter-gather data
 * @alloc:      binder_alloc associated with @buffer
 * @buffer:     binder buffer in target process
 * @sgc_head:   list_head of scatter-gather copy list
 * @pf_head:    list_head of pointer fixup list
 *
 * Processes all elements of @sgc_head, applying fixups from @pf_head
 * and copying the scatter-gather data from the source process' user
 * buffer to the target's buffer. It is expected that the list creation
 * and processing all occurs during binder_transaction() so these lists
 * are only accessed in local context.
 *
 * Return: 0=success, else -errno
 */
static int binder_do_deferred_txn_copies(struct binder_alloc *alloc,
                                         struct binder_buffer *buffer,
                                         struct list_head *sgc_head,
                                         struct list_head *pf_head)
{
        int ret = 0;
        struct binder_sg_copy *sgc, *tmpsgc;
        struct binder_ptr_fixup *tmppf;
        struct binder_ptr_fixup *pf =
                list_first_entry_or_null(pf_head, struct binder_ptr_fixup,
                                         node);

        list_for_each_entry_safe(sgc, tmpsgc, sgc_head, node) {
                size_t bytes_copied = 0;

                while (bytes_copied < sgc->length) {
                        size_t copy_size;
                        size_t bytes_left = sgc->length - bytes_copied;
                        size_t offset = sgc->offset + bytes_copied;

                        /*
                         * We copy up to the fixup (pointed to by pf)
                         */
                        copy_size = pf ? min(bytes_left, (size_t)pf->offset - offset)
                                       : bytes_left;
                        if (!ret && copy_size)
                                ret = binder_alloc_copy_user_to_buffer(
                                                alloc, buffer,
                                                offset,
                                                sgc->sender_uaddr + bytes_copied,
                                                copy_size);
                        bytes_copied += copy_size;
                        if (copy_size != bytes_left) {
                                BUG_ON(!pf);
                                /* we stopped at a fixup offset */
                                if (pf->skip_size) {
                                        /*
                                         * we are just skipping. This is for
                                         * BINDER_TYPE_FDA where the translated
                                         * fds will be fixed up when we get
                                         * to target context.
                                         */
                                        bytes_copied += pf->skip_size;
                                } else {
                                        /* apply the fixup indicated by pf */
                                        if (!ret)
                                                ret = binder_alloc_copy_to_buffer(
                                                        alloc, buffer,
                                                        pf->offset,
                                                        &pf->fixup_data,
                                                        sizeof(pf->fixup_data));
                                        bytes_copied += sizeof(pf->fixup_data);
                                }
                                list_del(&pf->node);
                                kfree(pf);
                                pf = list_first_entry_or_null(pf_head,
                                                struct binder_ptr_fixup, node);
                        }
                }
                list_del(&sgc->node);
                kfree(sgc);
        }
        list_for_each_entry_safe(pf, tmppf, pf_head, node) {
                BUG_ON(pf->skip_size == 0);
                list_del(&pf->node);
                kfree(pf);
        }
        BUG_ON(!list_empty(sgc_head));

        return ret > 0 ? -EINVAL : ret;
}

/**
 * binder_cleanup_deferred_txn_lists() - free specified lists
 * @sgc_head:   list_head of scatter-gather copy list
 * @pf_head:    list_head of pointer fixup list
 *
 * Called to clean up @sgc_head and @pf_head if there is an
 * error.
 */
static void binder_cleanup_deferred_txn_lists(struct list_head *sgc_head,
                                              struct list_head *pf_head)
{
        struct binder_sg_copy *sgc, *tmpsgc;
        struct binder_ptr_fixup *pf, *tmppf;

        list_for_each_entry_safe(sgc, tmpsgc, sgc_head, node) {
                list_del(&sgc->node);
                kfree(sgc);
        }
        list_for_each_entry_safe(pf, tmppf, pf_head, node) {
                list_del(&pf->node);
                kfree(pf);
        }
}

/**
 * binder_defer_copy() - queue a scatter-gather buffer for copy
 * @sgc_head:           list_head of scatter-gather copy list
 * @offset:             binder buffer offset in target process
 * @sender_uaddr:       user address in source process
 * @length:             bytes to copy
 *
 * Specify a scatter-gather block to be copied. The actual copy must
 * be deferred until all the needed fixups are identified and queued.
 * Then the copy and fixups are done together so un-translated values
 * from the source are never visible in the target buffer.
 *
 * We are guaranteed that repeated calls to this function will have
 * monotonically increasing @offset values so the list will naturally
 * be ordered.
 *
 * Return: 0=success, else -errno
 */
static int binder_defer_copy(struct list_head *sgc_head, binder_size_t offset,
                             const void __user *sender_uaddr, size_t length)
{
        struct binder_sg_copy *bc = kzalloc(sizeof(*bc), GFP_KERNEL);

        if (!bc)
                return -ENOMEM;

        bc->offset = offset;
        bc->sender_uaddr = sender_uaddr;
        bc->length = length;
        INIT_LIST_HEAD(&bc->node);

        /*
         * We are guaranteed that the deferred copies are in-order
         * so just add to the tail.
         */
        list_add_tail(&bc->node, sgc_head);

        return 0;
}

/**
 * binder_add_fixup() - queue a fixup to be applied to sg copy
 * @pf_head:    list_head of binder ptr fixup list
 * @offset:     binder buffer offset in target process
 * @fixup:      bytes to be copied for fixup
 * @skip_size:  bytes to skip when copying (fixup will be applied later)
 *
 * Add the specified fixup to a list ordered by @offset. When copying
 * the scatter-gather buffers, the fixup will be copied instead of
 * data from the source buffer. For BINDER_TYPE_FDA fixups, the fixup
 * will be applied later (in target process context), so we just skip
 * the bytes specified by @skip_size. If @skip_size is 0, we copy the
 * value in @fixup.
 *
 * This function is called *mostly* in @offset order, but there are
 * exceptions. Since out-of-order inserts are relatively uncommon,
 * we insert the new element by searching backward from the tail of
 * the list.
 *
 * Return: 0=success, else -errno
 */
static int binder_add_fixup(struct list_head *pf_head, binder_size_t offset,
                            binder_uintptr_t fixup, size_t skip_size)
{
        struct binder_ptr_fixup *pf = kzalloc(sizeof(*pf), GFP_KERNEL);
        struct binder_ptr_fixup *tmppf;

        if (!pf)
                return -ENOMEM;

        pf->offset = offset;
        pf->fixup_data = fixup;
        pf->skip_size = skip_size;
        INIT_LIST_HEAD(&pf->node);

        /* Fixups are *mostly* added in-order, but there are some
         * exceptions. Look backwards through list for insertion point.
         */
        list_for_each_entry_reverse(tmppf, pf_head, node) {
                if (tmppf->offset < pf->offset) {
                        list_add(&pf->node, &tmppf->node);
                        return 0;
                }
        }
        /*
         * if we get here, then the new offset is the lowest so
         * insert at the head
         */
        list_add(&pf->node, pf_head);
        return 0;
}

static int binder_translate_fd_array(struct list_head *pf_head,
                                     struct binder_fd_array_object *fda,
                                     const void __user *sender_ubuffer,
                                     struct binder_buffer_object *parent,
                                     struct binder_buffer_object *sender_uparent,
                                     struct binder_transaction *t,
                                     struct binder_thread *thread,
                                     struct binder_transaction *in_reply_to)
{
        binder_size_t fdi, fd_buf_size;
        binder_size_t fda_offset;
        const void __user *sender_ufda_base;
        struct binder_proc *proc = thread->proc;
        int ret;

        if (fda->num_fds == 0)
                return 0;

        fd_buf_size = sizeof(u32) * fda->num_fds;
        if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
                binder_user_error("%d:%d got transaction with invalid number of fds (%lld)\n",
                                  proc->pid, thread->pid, (u64)fda->num_fds);
                return -EINVAL;
        }
        if (fd_buf_size > parent->length ||
            fda->parent_offset > parent->length - fd_buf_size) {
                /* No space for all file descriptors here. */
                binder_user_error("%d:%d not enough space to store %lld fds in buffer\n",
                                  proc->pid, thread->pid, (u64)fda->num_fds);
                return -EINVAL;
        }
        /*
         * the source data for binder_buffer_object is visible
         * to user-space and the @buffer element is the user
         * pointer to the buffer_object containing the fd_array.
         * Convert the address to an offset relative to
         * the base of the transaction buffer.
         */
        fda_offset = parent->buffer - t->buffer->user_data +
                fda->parent_offset;
        sender_ufda_base = (void __user *)(uintptr_t)sender_uparent->buffer +
                                fda->parent_offset;

        if (!IS_ALIGNED((unsigned long)fda_offset, sizeof(u32)) ||
            !IS_ALIGNED((unsigned long)sender_ufda_base, sizeof(u32))) {
                binder_user_error("%d:%d parent offset not aligned correctly.\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }
        ret = binder_add_fixup(pf_head, fda_offset, 0, fda->num_fds * sizeof(u32));
        if (ret)
                return ret;

        for (fdi = 0; fdi < fda->num_fds; fdi++) {
                u32 fd;
                binder_size_t offset = fda_offset + fdi * sizeof(fd);
                binder_size_t sender_uoffset = fdi * sizeof(fd);

                ret = copy_from_user(&fd, sender_ufda_base + sender_uoffset, sizeof(fd));
                if (!ret)
                        ret = binder_translate_fd(fd, offset, t, thread,
                                                  in_reply_to);
                if (ret)
                        return ret > 0 ? -EINVAL : ret;
        }
        return 0;
}

static int binder_fixup_parent(struct list_head *pf_head,
                               struct binder_transaction *t,
                               struct binder_thread *thread,
                               struct binder_buffer_object *bp,
                               binder_size_t off_start_offset,
                               binder_size_t num_valid,
                               binder_size_t last_fixup_obj_off,
                               binder_size_t last_fixup_min_off)
{
        struct binder_buffer_object *parent;
        struct binder_buffer *b = t->buffer;
        struct binder_proc *proc = thread->proc;
        struct binder_proc *target_proc = t->to_proc;
        struct binder_object object;
        binder_size_t buffer_offset;
        binder_size_t parent_offset;

        if (!(bp->flags & BINDER_BUFFER_FLAG_HAS_PARENT))
                return 0;

        parent = binder_validate_ptr(target_proc, b, &object, bp->parent,
                                     off_start_offset, &parent_offset,
                                     num_valid);
        if (!parent) {
                binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }

        if (!binder_validate_fixup(target_proc, b, off_start_offset,
                                   parent_offset, bp->parent_offset,
                                   last_fixup_obj_off,
                                   last_fixup_min_off)) {
                binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }

        if (parent->length < sizeof(binder_uintptr_t) ||
            bp->parent_offset > parent->length - sizeof(binder_uintptr_t)) {
                /* No space for a pointer here! */
                binder_user_error("%d:%d got transaction with invalid parent offset\n",
                                  proc->pid, thread->pid);
                return -EINVAL;
        }

        buffer_offset = bp->parent_offset + parent->buffer - b->user_data;

        return binder_add_fixup(pf_head, buffer_offset, bp->buffer, 0);
}

/**
 * binder_can_update_transaction() - Can a txn be superseded by an updated one?
 * @t1: the pending async txn in the frozen process
 * @t2: the new async txn to supersede the outdated pending one
 *
 * Return:  true if t2 can supersede t1
 *          false if t2 can not supersede t1
 */
static bool binder_can_update_transaction(struct binder_transaction *t1,
                                          struct binder_transaction *t2)
{
        if ((t1->flags & t2->flags & (TF_ONE_WAY | TF_UPDATE_TXN)) !=
            (TF_ONE_WAY | TF_UPDATE_TXN) || !t1->to_proc || !t2->to_proc)
                return false;
        if (t1->to_proc->tsk == t2->to_proc->tsk && t1->code == t2->code &&
            t1->flags == t2->flags && t1->buffer->pid == t2->buffer->pid &&
            t1->buffer->target_node->ptr == t2->buffer->target_node->ptr &&
            t1->buffer->target_node->cookie == t2->buffer->target_node->cookie)
                return true;
        return false;
}

/**
 * binder_find_outdated_transaction_ilocked() - Find the outdated transaction
 * @t:           new async transaction
 * @target_list: list to find outdated transaction
 *
 * Return: the outdated transaction if found
 *         NULL if no outdated transacton can be found
 *
 * Requires the proc->inner_lock to be held.
 */
static struct binder_transaction *
binder_find_outdated_transaction_ilocked(struct binder_transaction *t,
                                         struct list_head *target_list)
{
        struct binder_work *w;

        list_for_each_entry(w, target_list, entry) {
                struct binder_transaction *t_queued;

                if (w->type != BINDER_WORK_TRANSACTION)
                        continue;
                t_queued = container_of(w, struct binder_transaction, work);
                if (binder_can_update_transaction(t_queued, t))
                        return t_queued;
        }
        return NULL;
}

/**
 * binder_proc_transaction() - sends a transaction to a process and wakes it up
 * @t:          transaction to send
 * @proc:       process to send the transaction to
 * @thread:     thread in @proc to send the transaction to (may be NULL)
 *
 * This function queues a transaction to the specified process. It will try
 * to find a thread in the target process to handle the transaction and
 * wake it up. If no thread is found, the work is queued to the proc
 * waitqueue.
 *
 * If the @thread parameter is not NULL, the transaction is always queued
 * to the waitlist of that specific thread.
 *
 * Return:      0 if the transaction was successfully queued
 *              BR_DEAD_REPLY if the target process or thread is dead
 *              BR_FROZEN_REPLY if the target process or thread is frozen and
 *                      the sync transaction was rejected
 *              BR_TRANSACTION_PENDING_FROZEN if the target process is frozen
 *              and the async transaction was successfully queued
 */
static int binder_proc_transaction(struct binder_transaction *t,
                                    struct binder_proc *proc,
                                    struct binder_thread *thread)
{
        struct binder_node *node = t->buffer->target_node;
        bool oneway = !!(t->flags & TF_ONE_WAY);
        bool pending_async = false;
        struct binder_transaction *t_outdated = NULL;
        bool frozen = false;

        BUG_ON(!node);
        binder_node_lock(node);
        if (oneway) {
                BUG_ON(thread);
                if (node->has_async_transaction)
                        pending_async = true;
                else
                        node->has_async_transaction = true;
        }

        binder_inner_proc_lock(proc);
        if (proc->is_frozen) {
                frozen = true;
                proc->sync_recv |= !oneway;
                proc->async_recv |= oneway;
        }

        if ((frozen && !oneway) || proc->is_dead ||
                        (thread && thread->is_dead)) {
                binder_inner_proc_unlock(proc);
                binder_node_unlock(node);
                return frozen ? BR_FROZEN_REPLY : BR_DEAD_REPLY;
        }

        if (!thread && !pending_async)
                thread = binder_select_thread_ilocked(proc);

        if (thread) {
                binder_enqueue_thread_work_ilocked(thread, &t->work);
        } else if (!pending_async) {
                binder_enqueue_work_ilocked(&t->work, &proc->todo);
        } else {
                if ((t->flags & TF_UPDATE_TXN) && frozen) {
                        t_outdated = binder_find_outdated_transaction_ilocked(t,
                                                                              &node->async_todo);
                        if (t_outdated) {
                                binder_debug(BINDER_DEBUG_TRANSACTION,
                                             "txn %d supersedes %d\n",
                                             t->debug_id, t_outdated->debug_id);
                                list_del_init(&t_outdated->work.entry);
                                proc->outstanding_txns--;
                        }
                }
                binder_enqueue_work_ilocked(&t->work, &node->async_todo);
        }

        if (!pending_async)
                binder_wakeup_thread_ilocked(proc, thread, !oneway /* sync */);

        proc->outstanding_txns++;
        binder_inner_proc_unlock(proc);
        binder_node_unlock(node);

        /*
         * To reduce potential contention, free the outdated transaction and
         * buffer after releasing the locks.
         */
        if (t_outdated) {
                struct binder_buffer *buffer = t_outdated->buffer;

                t_outdated->buffer = NULL;
                buffer->transaction = NULL;
                trace_binder_transaction_update_buffer_release(buffer);
                binder_release_entire_buffer(proc, NULL, buffer, false);
                binder_alloc_free_buf(&proc->alloc, buffer);
                kfree(t_outdated);
                binder_stats_deleted(BINDER_STAT_TRANSACTION);
        }

        if (oneway && frozen)
                return BR_TRANSACTION_PENDING_FROZEN;

        return 0;
}

/**
 * binder_get_node_refs_for_txn() - Get required refs on node for txn
 * @node:         struct binder_node for which to get refs
 * @procp:        returns @node->proc if valid
 * @error:        if no @procp then returns BR_DEAD_REPLY
 *
 * User-space normally keeps the node alive when creating a transaction
 * since it has a reference to the target. The local strong ref keeps it
 * alive if the sending process dies before the target process processes
 * the transaction. If the source process is malicious or has a reference
 * counting bug, relying on the local strong ref can fail.
 *
 * Since user-space can cause the local strong ref to go away, we also take
 * a tmpref on the node to ensure it survives while we are constructing
 * the transaction. We also need a tmpref on the proc while we are
 * constructing the transaction, so we take that here as well.
 *
 * Return: The target_node with refs taken or NULL if no @node->proc is NULL.
 * Also sets @procp if valid. If the @node->proc is NULL indicating that the
 * target proc has died, @error is set to BR_DEAD_REPLY.
 */
static struct binder_node *binder_get_node_refs_for_txn(
                struct binder_node *node,
                struct binder_proc **procp,
                uint32_t *error)
{
        struct binder_node *target_node = NULL;

        binder_node_inner_lock(node);
        if (node->proc) {
                target_node = node;
                binder_inc_node_nilocked(node, 1, 0, NULL);
                binder_inc_node_tmpref_ilocked(node);
                node->proc->tmp_ref++;
                *procp = node->proc;
        } else
                *error = BR_DEAD_REPLY;
        binder_node_inner_unlock(node);

        return target_node;
}

static void binder_set_txn_from_error(struct binder_transaction *t, int id,
                                      uint32_t command, int32_t param)
{
        struct binder_thread *from = binder_get_txn_from_and_acq_inner(t);

        if (!from) {
                /* annotation for sparse */
                __release(&from->proc->inner_lock);
                return;
        }

        /* don't override existing errors */
        if (from->ee.command == BR_OK)
                binder_set_extended_error(&from->ee, id, command, param);
        binder_inner_proc_unlock(from->proc);
        binder_thread_dec_tmpref(from);
}

static void binder_transaction(struct binder_proc *proc,
                               struct binder_thread *thread,
                               struct binder_transaction_data *tr, int reply,
                               binder_size_t extra_buffers_size)
{
        int ret;
        struct binder_transaction *t;
        struct binder_work *w;
        struct binder_work *tcomplete;
        binder_size_t buffer_offset = 0;
        binder_size_t off_start_offset, off_end_offset;
        binder_size_t off_min;
        binder_size_t sg_buf_offset, sg_buf_end_offset;
        binder_size_t user_offset = 0;
        struct binder_proc *target_proc = NULL;
        struct binder_thread *target_thread = NULL;
        struct binder_node *target_node = NULL;
        struct binder_transaction *in_reply_to = NULL;
        struct binder_transaction_log_entry *e;
        uint32_t return_error = 0;
        uint32_t return_error_param = 0;
        uint32_t return_error_line = 0;
        binder_size_t last_fixup_obj_off = 0;
        binder_size_t last_fixup_min_off = 0;
        struct binder_context *context = proc->context;
        int t_debug_id = atomic_inc_return(&binder_last_id);
        ktime_t t_start_time = ktime_get();
        struct lsm_context lsmctx = { };
        struct list_head sgc_head;
        struct list_head pf_head;
        const void __user *user_buffer = (const void __user *)
                                (uintptr_t)tr->data.ptr.buffer;
        INIT_LIST_HEAD(&sgc_head);
        INIT_LIST_HEAD(&pf_head);

        e = binder_transaction_log_add(&binder_transaction_log);
        e->debug_id = t_debug_id;
        e->call_type = reply ? 2 : !!(tr->flags & TF_ONE_WAY);
        e->from_proc = proc->pid;
        e->from_thread = thread->pid;
        e->target_handle = tr->target.handle;
        e->data_size = tr->data_size;
        e->offsets_size = tr->offsets_size;
        strscpy(e->context_name, proc->context->name, BINDERFS_MAX_NAME);

        binder_inner_proc_lock(proc);
        binder_set_extended_error(&thread->ee, t_debug_id, BR_OK, 0);
        binder_inner_proc_unlock(proc);

        if (reply) {
                binder_inner_proc_lock(proc);
                in_reply_to = thread->transaction_stack;
                if (in_reply_to == NULL) {
                        binder_inner_proc_unlock(proc);
                        binder_user_error("%d:%d got reply transaction with no transaction stack\n",
                                          proc->pid, thread->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        goto err_empty_call_stack;
                }
                if (in_reply_to->to_thread != thread) {
                        spin_lock(&in_reply_to->lock);
                        binder_user_error("%d:%d got reply transaction with bad transaction stack, transaction %d has target %d:%d\n",
                                proc->pid, thread->pid, in_reply_to->debug_id,
                                in_reply_to->to_proc ?
                                in_reply_to->to_proc->pid : 0,
                                in_reply_to->to_thread ?
                                in_reply_to->to_thread->pid : 0);
                        spin_unlock(&in_reply_to->lock);
                        binder_inner_proc_unlock(proc);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        in_reply_to = NULL;
                        goto err_bad_call_stack;
                }
                thread->transaction_stack = in_reply_to->to_parent;
                binder_inner_proc_unlock(proc);
                binder_set_nice(in_reply_to->saved_priority);
                target_thread = binder_get_txn_from_and_acq_inner(in_reply_to);
                if (target_thread == NULL) {
                        /* annotation for sparse */
                        __release(&target_thread->proc->inner_lock);
                        binder_txn_error("%d:%d reply target not found\n",
                                thread->pid, proc->pid);
                        return_error = BR_DEAD_REPLY;
                        return_error_line = __LINE__;
                        goto err_dead_binder;
                }
                if (target_thread->transaction_stack != in_reply_to) {
                        binder_user_error("%d:%d got reply transaction with bad target transaction stack %d, expected %d\n",
                                proc->pid, thread->pid,
                                target_thread->transaction_stack ?
                                target_thread->transaction_stack->debug_id : 0,
                                in_reply_to->debug_id);
                        binder_inner_proc_unlock(target_thread->proc);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        in_reply_to = NULL;
                        target_thread = NULL;
                        goto err_dead_binder;
                }
                target_proc = target_thread->proc;
                target_proc->tmp_ref++;
                binder_inner_proc_unlock(target_thread->proc);
        } else {
                if (tr->target.handle) {
                        struct binder_ref *ref;

                        /*
                         * There must already be a strong ref
                         * on this node. If so, do a strong
                         * increment on the node to ensure it
                         * stays alive until the transaction is
                         * done.
                         */
                        binder_proc_lock(proc);
                        ref = binder_get_ref_olocked(proc, tr->target.handle,
                                                     true);
                        if (ref) {
                                target_node = binder_get_node_refs_for_txn(
                                                ref->node, &target_proc,
                                                &return_error);
                        } else {
                                binder_user_error("%d:%d got transaction to invalid handle, %u\n",
                                                  proc->pid, thread->pid, tr->target.handle);
                                return_error = BR_FAILED_REPLY;
                        }
                        binder_proc_unlock(proc);
                } else {
                        mutex_lock(&context->context_mgr_node_lock);
                        target_node = context->binder_context_mgr_node;
                        if (target_node)
                                target_node = binder_get_node_refs_for_txn(
                                                target_node, &target_proc,
                                                &return_error);
                        else
                                return_error = BR_DEAD_REPLY;
                        mutex_unlock(&context->context_mgr_node_lock);
                        if (target_node && target_proc->pid == proc->pid) {
                                binder_user_error("%d:%d got transaction to context manager from process owning it\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_invalid_target_handle;
                        }
                }
                if (!target_node) {
                        binder_txn_error("%d:%d cannot find target node\n",
                                thread->pid, proc->pid);
                        /*
                         * return_error is set above
                         */
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_dead_binder;
                }
                e->to_node = target_node->debug_id;
                if (WARN_ON(proc == target_proc)) {
                        binder_txn_error("%d:%d self transactions not allowed\n",
                                thread->pid, proc->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_invalid_target_handle;
                }
                if (security_binder_transaction(proc->cred,
                                                target_proc->cred) < 0) {
                        binder_txn_error("%d:%d transaction credentials failed\n",
                                thread->pid, proc->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPERM;
                        return_error_line = __LINE__;
                        goto err_invalid_target_handle;
                }
                binder_inner_proc_lock(proc);

                w = list_first_entry_or_null(&thread->todo,
                                             struct binder_work, entry);
                if (!(tr->flags & TF_ONE_WAY) && w &&
                    w->type == BINDER_WORK_TRANSACTION) {
                        /*
                         * Do not allow new outgoing transaction from a
                         * thread that has a transaction at the head of
                         * its todo list. Only need to check the head
                         * because binder_select_thread_ilocked picks a
                         * thread from proc->waiting_threads to enqueue
                         * the transaction, and nothing is queued to the
                         * todo list while the thread is on waiting_threads.
                         */
                        binder_user_error("%d:%d new transaction not allowed when there is a transaction on thread todo\n",
                                          proc->pid, thread->pid);
                        binder_inner_proc_unlock(proc);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EPROTO;
                        return_error_line = __LINE__;
                        goto err_bad_todo_list;
                }

                if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
                        struct binder_transaction *tmp;

                        tmp = thread->transaction_stack;
                        if (tmp->to_thread != thread) {
                                spin_lock(&tmp->lock);
                                binder_user_error("%d:%d got new transaction with bad transaction stack, transaction %d has target %d:%d\n",
                                        proc->pid, thread->pid, tmp->debug_id,
                                        tmp->to_proc ? tmp->to_proc->pid : 0,
                                        tmp->to_thread ?
                                        tmp->to_thread->pid : 0);
                                spin_unlock(&tmp->lock);
                                binder_inner_proc_unlock(proc);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EPROTO;
                                return_error_line = __LINE__;
                                goto err_bad_call_stack;
                        }
                        while (tmp) {
                                struct binder_thread *from;

                                spin_lock(&tmp->lock);
                                from = tmp->from;
                                if (from && from->proc == target_proc) {
                                        atomic_inc(&from->tmp_ref);
                                        target_thread = from;
                                        spin_unlock(&tmp->lock);
                                        break;
                                }
                                spin_unlock(&tmp->lock);
                                tmp = tmp->from_parent;
                        }
                }
                binder_inner_proc_unlock(proc);
        }
        if (target_thread)
                e->to_thread = target_thread->pid;
        e->to_proc = target_proc->pid;

        /* TODO: reuse incoming transaction for reply */
        t = kzalloc(sizeof(*t), GFP_KERNEL);
        if (t == NULL) {
                binder_txn_error("%d:%d cannot allocate transaction\n",
                        thread->pid, proc->pid);
                return_error = BR_FAILED_REPLY;
                return_error_param = -ENOMEM;
                return_error_line = __LINE__;
                goto err_alloc_t_failed;
        }
        INIT_LIST_HEAD(&t->fd_fixups);
        binder_stats_created(BINDER_STAT_TRANSACTION);
        spin_lock_init(&t->lock);

        tcomplete = kzalloc(sizeof(*tcomplete), GFP_KERNEL);
        if (tcomplete == NULL) {
                binder_txn_error("%d:%d cannot allocate work for transaction\n",
                        thread->pid, proc->pid);
                return_error = BR_FAILED_REPLY;
                return_error_param = -ENOMEM;
                return_error_line = __LINE__;
                goto err_alloc_tcomplete_failed;
        }
        binder_stats_created(BINDER_STAT_TRANSACTION_COMPLETE);

        t->debug_id = t_debug_id;
        t->start_time = t_start_time;

        if (reply)
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d BC_REPLY %d -> %d:%d, data %016llx-%016llx size %lld-%lld-%lld\n",
                             proc->pid, thread->pid, t->debug_id,
                             target_proc->pid, target_thread->pid,
                             (u64)tr->data.ptr.buffer,
                             (u64)tr->data.ptr.offsets,
                             (u64)tr->data_size, (u64)tr->offsets_size,
                             (u64)extra_buffers_size);
        else
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d BC_TRANSACTION %d -> %d - node %d, data %016llx-%016llx size %lld-%lld-%lld\n",
                             proc->pid, thread->pid, t->debug_id,
                             target_proc->pid, target_node->debug_id,
                             (u64)tr->data.ptr.buffer,
                             (u64)tr->data.ptr.offsets,
                             (u64)tr->data_size, (u64)tr->offsets_size,
                             (u64)extra_buffers_size);

        if (!reply && !(tr->flags & TF_ONE_WAY))
                t->from = thread;
        else
                t->from = NULL;
        t->from_pid = proc->pid;
        t->from_tid = thread->pid;
        t->sender_euid = task_euid(proc->tsk);
        t->to_proc = target_proc;
        t->to_thread = target_thread;
        t->code = tr->code;
        t->flags = tr->flags;
        t->priority = task_nice(current);

        if (target_node && target_node->txn_security_ctx) {
                u32 secid;
                size_t added_size;

                security_cred_getsecid(proc->cred, &secid);
                ret = security_secid_to_secctx(secid, &lsmctx);
                if (ret < 0) {
                        binder_txn_error("%d:%d failed to get security context\n",
                                thread->pid, proc->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = ret;
                        return_error_line = __LINE__;
                        goto err_get_secctx_failed;
                }
                added_size = ALIGN(lsmctx.len, sizeof(u64));
                extra_buffers_size += added_size;
                if (extra_buffers_size < added_size) {
                        binder_txn_error("%d:%d integer overflow of extra_buffers_size\n",
                                thread->pid, proc->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_bad_extra_size;
                }
        }

        trace_binder_transaction(reply, t, target_node);

        t->buffer = binder_alloc_new_buf(&target_proc->alloc, tr->data_size,
                tr->offsets_size, extra_buffers_size,
                !reply && (t->flags & TF_ONE_WAY));
        if (IS_ERR(t->buffer)) {
                char *s;

                ret = PTR_ERR(t->buffer);
                s = (ret == -ESRCH) ? ": vma cleared, target dead or dying"
                        : (ret == -ENOSPC) ? ": no space left"
                        : (ret == -ENOMEM) ? ": memory allocation failed"
                        : "";
                binder_txn_error("cannot allocate buffer%s", s);

                return_error_param = PTR_ERR(t->buffer);
                return_error = return_error_param == -ESRCH ?
                        BR_DEAD_REPLY : BR_FAILED_REPLY;
                return_error_line = __LINE__;
                t->buffer = NULL;
                goto err_binder_alloc_buf_failed;
        }
        if (lsmctx.context) {
                int err;
                size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) +
                                    ALIGN(tr->offsets_size, sizeof(void *)) +
                                    ALIGN(extra_buffers_size, sizeof(void *)) -
                                    ALIGN(lsmctx.len, sizeof(u64));

                t->security_ctx = t->buffer->user_data + buf_offset;
                err = binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                  t->buffer, buf_offset,
                                                  lsmctx.context, lsmctx.len);
                if (err) {
                        t->security_ctx = 0;
                        WARN_ON(1);
                }
                security_release_secctx(&lsmctx);
                lsmctx.context = NULL;
        }
        t->buffer->debug_id = t->debug_id;
        t->buffer->transaction = t;
        t->buffer->target_node = target_node;
        t->buffer->clear_on_free = !!(t->flags & TF_CLEAR_BUF);
        trace_binder_transaction_alloc_buf(t->buffer);

        if (binder_alloc_copy_user_to_buffer(
                                &target_proc->alloc,
                                t->buffer,
                                ALIGN(tr->data_size, sizeof(void *)),
                                (const void __user *)
                                        (uintptr_t)tr->data.ptr.offsets,
                                tr->offsets_size)) {
                binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
                                proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EFAULT;
                return_error_line = __LINE__;
                goto err_copy_data_failed;
        }
        if (!IS_ALIGNED(tr->offsets_size, sizeof(binder_size_t))) {
                binder_user_error("%d:%d got transaction with invalid offsets size, %lld\n",
                                proc->pid, thread->pid, (u64)tr->offsets_size);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EINVAL;
                return_error_line = __LINE__;
                goto err_bad_offset;
        }
        if (!IS_ALIGNED(extra_buffers_size, sizeof(u64))) {
                binder_user_error("%d:%d got transaction with unaligned buffers size, %lld\n",
                                  proc->pid, thread->pid,
                                  (u64)extra_buffers_size);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EINVAL;
                return_error_line = __LINE__;
                goto err_bad_offset;
        }
        off_start_offset = ALIGN(tr->data_size, sizeof(void *));
        buffer_offset = off_start_offset;
        off_end_offset = off_start_offset + tr->offsets_size;
        sg_buf_offset = ALIGN(off_end_offset, sizeof(void *));
        sg_buf_end_offset = sg_buf_offset + extra_buffers_size -
                ALIGN(lsmctx.len, sizeof(u64));
        off_min = 0;
        for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
             buffer_offset += sizeof(binder_size_t)) {
                struct binder_object_header *hdr;
                size_t object_size;
                struct binder_object object;
                binder_size_t object_offset;
                binder_size_t copy_size;

                if (binder_alloc_copy_from_buffer(&target_proc->alloc,
                                                  &object_offset,
                                                  t->buffer,
                                                  buffer_offset,
                                                  sizeof(object_offset))) {
                        binder_txn_error("%d:%d copy offset from buffer failed\n",
                                thread->pid, proc->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_bad_offset;
                }

                /*
                 * Copy the source user buffer up to the next object
                 * that will be processed.
                 */
                copy_size = object_offset - user_offset;
                if (copy_size && (user_offset > object_offset ||
                                object_offset > tr->data_size ||
                                binder_alloc_copy_user_to_buffer(
                                        &target_proc->alloc,
                                        t->buffer, user_offset,
                                        user_buffer + user_offset,
                                        copy_size))) {
                        binder_user_error("%d:%d got transaction with invalid data ptr\n",
                                        proc->pid, thread->pid);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EFAULT;
                        return_error_line = __LINE__;
                        goto err_copy_data_failed;
                }
                object_size = binder_get_object(target_proc, user_buffer,
                                t->buffer, object_offset, &object);
                if (object_size == 0 || object_offset < off_min) {
                        binder_user_error("%d:%d got transaction with invalid offset (%lld, min %lld max %lld) or object.\n",
                                          proc->pid, thread->pid,
                                          (u64)object_offset,
                                          (u64)off_min,
                                          (u64)t->buffer->data_size);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_bad_offset;
                }
                /*
                 * Set offset to the next buffer fragment to be
                 * copied
                 */
                user_offset = object_offset + object_size;

                hdr = &object.hdr;
                off_min = object_offset + object_size;
                switch (hdr->type) {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER: {
                        struct flat_binder_object *fp;

                        fp = to_flat_binder_object(hdr);
                        ret = binder_translate_binder(fp, t, thread);

                        if (ret < 0 ||
                            binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                        t->buffer,
                                                        object_offset,
                                                        fp, sizeof(*fp))) {
                                binder_txn_error("%d:%d translate binder failed\n",
                                        thread->pid, proc->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                } break;
                case BINDER_TYPE_HANDLE:
                case BINDER_TYPE_WEAK_HANDLE: {
                        struct flat_binder_object *fp;

                        fp = to_flat_binder_object(hdr);
                        ret = binder_translate_handle(fp, t, thread);
                        if (ret < 0 ||
                            binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                        t->buffer,
                                                        object_offset,
                                                        fp, sizeof(*fp))) {
                                binder_txn_error("%d:%d translate handle failed\n",
                                        thread->pid, proc->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                } break;

                case BINDER_TYPE_FD: {
                        struct binder_fd_object *fp = to_binder_fd_object(hdr);
                        binder_size_t fd_offset = object_offset +
                                (uintptr_t)&fp->fd - (uintptr_t)fp;
                        int ret = binder_translate_fd(fp->fd, fd_offset, t,
                                                      thread, in_reply_to);

                        fp->pad_binder = 0;
                        if (ret < 0 ||
                            binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                        t->buffer,
                                                        object_offset,
                                                        fp, sizeof(*fp))) {
                                binder_txn_error("%d:%d translate fd failed\n",
                                        thread->pid, proc->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                } break;
                case BINDER_TYPE_FDA: {
                        struct binder_object ptr_object;
                        binder_size_t parent_offset;
                        struct binder_object user_object;
                        size_t user_parent_size;
                        struct binder_fd_array_object *fda =
                                to_binder_fd_array_object(hdr);
                        size_t num_valid = (buffer_offset - off_start_offset) /
                                                sizeof(binder_size_t);
                        struct binder_buffer_object *parent =
                                binder_validate_ptr(target_proc, t->buffer,
                                                    &ptr_object, fda->parent,
                                                    off_start_offset,
                                                    &parent_offset,
                                                    num_valid);
                        if (!parent) {
                                binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_bad_parent;
                        }
                        if (!binder_validate_fixup(target_proc, t->buffer,
                                                   off_start_offset,
                                                   parent_offset,
                                                   fda->parent_offset,
                                                   last_fixup_obj_off,
                                                   last_fixup_min_off)) {
                                binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_bad_parent;
                        }
                        /*
                         * We need to read the user version of the parent
                         * object to get the original user offset
                         */
                        user_parent_size =
                                binder_get_object(proc, user_buffer, t->buffer,
                                                  parent_offset, &user_object);
                        if (user_parent_size != sizeof(user_object.bbo)) {
                                binder_user_error("%d:%d invalid ptr object size: %zd vs %zd\n",
                                                  proc->pid, thread->pid,
                                                  user_parent_size,
                                                  sizeof(user_object.bbo));
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_bad_parent;
                        }
                        ret = binder_translate_fd_array(&pf_head, fda,
                                                        user_buffer, parent,
                                                        &user_object.bbo, t,
                                                        thread, in_reply_to);
                        if (!ret)
                                ret = binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                                  t->buffer,
                                                                  object_offset,
                                                                  fda, sizeof(*fda));
                        if (ret) {
                                binder_txn_error("%d:%d translate fd array failed\n",
                                        thread->pid, proc->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret > 0 ? -EINVAL : ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                        last_fixup_obj_off = parent_offset;
                        last_fixup_min_off =
                                fda->parent_offset + sizeof(u32) * fda->num_fds;
                } break;
                case BINDER_TYPE_PTR: {
                        struct binder_buffer_object *bp =
                                to_binder_buffer_object(hdr);
                        size_t buf_left = sg_buf_end_offset - sg_buf_offset;
                        size_t num_valid;

                        if (bp->length > buf_left) {
                                binder_user_error("%d:%d got transaction with too large buffer\n",
                                                  proc->pid, thread->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = -EINVAL;
                                return_error_line = __LINE__;
                                goto err_bad_offset;
                        }
                        ret = binder_defer_copy(&sgc_head, sg_buf_offset,
                                (const void __user *)(uintptr_t)bp->buffer,
                                bp->length);
                        if (ret) {
                                binder_txn_error("%d:%d deferred copy failed\n",
                                        thread->pid, proc->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                        /* Fixup buffer pointer to target proc address space */
                        bp->buffer = t->buffer->user_data + sg_buf_offset;
                        sg_buf_offset += ALIGN(bp->length, sizeof(u64));

                        num_valid = (buffer_offset - off_start_offset) /
                                        sizeof(binder_size_t);
                        ret = binder_fixup_parent(&pf_head, t,
                                                  thread, bp,
                                                  off_start_offset,
                                                  num_valid,
                                                  last_fixup_obj_off,
                                                  last_fixup_min_off);
                        if (ret < 0 ||
                            binder_alloc_copy_to_buffer(&target_proc->alloc,
                                                        t->buffer,
                                                        object_offset,
                                                        bp, sizeof(*bp))) {
                                binder_txn_error("%d:%d failed to fixup parent\n",
                                        thread->pid, proc->pid);
                                return_error = BR_FAILED_REPLY;
                                return_error_param = ret;
                                return_error_line = __LINE__;
                                goto err_translate_failed;
                        }
                        last_fixup_obj_off = object_offset;
                        last_fixup_min_off = 0;
                } break;
                default:
                        binder_user_error("%d:%d got transaction with invalid object type, %x\n",
                                proc->pid, thread->pid, hdr->type);
                        return_error = BR_FAILED_REPLY;
                        return_error_param = -EINVAL;
                        return_error_line = __LINE__;
                        goto err_bad_object_type;
                }
        }
        /* Done processing objects, copy the rest of the buffer */
        if (binder_alloc_copy_user_to_buffer(
                                &target_proc->alloc,
                                t->buffer, user_offset,
                                user_buffer + user_offset,
                                tr->data_size - user_offset)) {
                binder_user_error("%d:%d got transaction with invalid data ptr\n",
                                proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                return_error_param = -EFAULT;
                return_error_line = __LINE__;
                goto err_copy_data_failed;
        }

        ret = binder_do_deferred_txn_copies(&target_proc->alloc, t->buffer,
                                            &sgc_head, &pf_head);
        if (ret) {
                binder_user_error("%d:%d got transaction with invalid offsets ptr\n",
                                  proc->pid, thread->pid);
                return_error = BR_FAILED_REPLY;
                return_error_param = ret;
                return_error_line = __LINE__;
                goto err_copy_data_failed;
        }
        if (t->buffer->oneway_spam_suspect)
                tcomplete->type = BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT;
        else
                tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
        t->work.type = BINDER_WORK_TRANSACTION;

        if (reply) {
                binder_enqueue_thread_work(thread, tcomplete);
                binder_inner_proc_lock(target_proc);
                if (target_thread->is_dead) {
                        return_error = BR_DEAD_REPLY;
                        binder_inner_proc_unlock(target_proc);
                        goto err_dead_proc_or_thread;
                }
                BUG_ON(t->buffer->async_transaction != 0);
                binder_pop_transaction_ilocked(target_thread, in_reply_to);
                binder_enqueue_thread_work_ilocked(target_thread, &t->work);
                target_proc->outstanding_txns++;
                binder_inner_proc_unlock(target_proc);
                wake_up_interruptible_sync(&target_thread->wait);
                binder_free_transaction(in_reply_to);
        } else if (!(t->flags & TF_ONE_WAY)) {
                BUG_ON(t->buffer->async_transaction != 0);
                binder_inner_proc_lock(proc);
                /*
                 * Defer the TRANSACTION_COMPLETE, so we don't return to
                 * userspace immediately; this allows the target process to
                 * immediately start processing this transaction, reducing
                 * latency. We will then return the TRANSACTION_COMPLETE when
                 * the target replies (or there is an error).
                 */
                binder_enqueue_deferred_thread_work_ilocked(thread, tcomplete);
                t->need_reply = 1;
                t->from_parent = thread->transaction_stack;
                thread->transaction_stack = t;
                binder_inner_proc_unlock(proc);
                return_error = binder_proc_transaction(t,
                                target_proc, target_thread);
                if (return_error) {
                        binder_inner_proc_lock(proc);
                        binder_pop_transaction_ilocked(thread, t);
                        binder_inner_proc_unlock(proc);
                        goto err_dead_proc_or_thread;
                }
        } else {
                BUG_ON(target_node == NULL);
                BUG_ON(t->buffer->async_transaction != 1);
                return_error = binder_proc_transaction(t, target_proc, NULL);
                /*
                 * Let the caller know when async transaction reaches a frozen
                 * process and is put in a pending queue, waiting for the target
                 * process to be unfrozen.
                 */
                if (return_error == BR_TRANSACTION_PENDING_FROZEN)
                        tcomplete->type = BINDER_WORK_TRANSACTION_PENDING;
                binder_enqueue_thread_work(thread, tcomplete);
                if (return_error &&
                    return_error != BR_TRANSACTION_PENDING_FROZEN)
                        goto err_dead_proc_or_thread;
        }
        if (target_thread)
                binder_thread_dec_tmpref(target_thread);
        binder_proc_dec_tmpref(target_proc);
        if (target_node)
                binder_dec_node_tmpref(target_node);
        /*
         * write barrier to synchronize with initialization
         * of log entry
         */
        smp_wmb();
        WRITE_ONCE(e->debug_id_done, t_debug_id);
        return;

err_dead_proc_or_thread:
        binder_txn_error("%d:%d dead process or thread\n",
                thread->pid, proc->pid);
        return_error_line = __LINE__;
        binder_dequeue_work(proc, tcomplete);
err_translate_failed:
err_bad_object_type:
err_bad_offset:
err_bad_parent:
err_copy_data_failed:
        binder_cleanup_deferred_txn_lists(&sgc_head, &pf_head);
        binder_free_txn_fixups(t);
        trace_binder_transaction_failed_buffer_release(t->buffer);
        binder_transaction_buffer_release(target_proc, NULL, t->buffer,
                                          buffer_offset, true);
        if (target_node)
                binder_dec_node_tmpref(target_node);
        target_node = NULL;
        t->buffer->transaction = NULL;
        binder_alloc_free_buf(&target_proc->alloc, t->buffer);
err_binder_alloc_buf_failed:
err_bad_extra_size:
        if (lsmctx.context)
                security_release_secctx(&lsmctx);
err_get_secctx_failed:
        kfree(tcomplete);
        binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
err_alloc_tcomplete_failed:
        if (trace_binder_txn_latency_free_enabled())
                binder_txn_latency_free(t);
        kfree(t);
        binder_stats_deleted(BINDER_STAT_TRANSACTION);
err_alloc_t_failed:
err_bad_todo_list:
err_bad_call_stack:
err_empty_call_stack:
err_dead_binder:
err_invalid_target_handle:
        if (target_node) {
                binder_dec_node(target_node, 1, 0);
                binder_dec_node_tmpref(target_node);
        }

        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                     "%d:%d transaction %s to %d:%d failed %d/%d/%d, size %lld-%lld line %d\n",
                     proc->pid, thread->pid, reply ? "reply" :
                     (tr->flags & TF_ONE_WAY ? "async" : "call"),
                     target_proc ? target_proc->pid : 0,
                     target_thread ? target_thread->pid : 0,
                     t_debug_id, return_error, return_error_param,
                     (u64)tr->data_size, (u64)tr->offsets_size,
                     return_error_line);

        if (target_thread)
                binder_thread_dec_tmpref(target_thread);
        if (target_proc)
                binder_proc_dec_tmpref(target_proc);

        {
                struct binder_transaction_log_entry *fe;

                e->return_error = return_error;
                e->return_error_param = return_error_param;
                e->return_error_line = return_error_line;
                fe = binder_transaction_log_add(&binder_transaction_log_failed);
                *fe = *e;
                /*
                 * write barrier to synchronize with initialization
                 * of log entry
                 */
                smp_wmb();
                WRITE_ONCE(e->debug_id_done, t_debug_id);
                WRITE_ONCE(fe->debug_id_done, t_debug_id);
        }

        BUG_ON(thread->return_error.cmd != BR_OK);
        if (in_reply_to) {
                binder_set_txn_from_error(in_reply_to, t_debug_id,
                                return_error, return_error_param);
                thread->return_error.cmd = BR_TRANSACTION_COMPLETE;
                binder_enqueue_thread_work(thread, &thread->return_error.work);
                binder_send_failed_reply(in_reply_to, return_error);
        } else {
                binder_inner_proc_lock(proc);
                binder_set_extended_error(&thread->ee, t_debug_id,
                                return_error, return_error_param);
                binder_inner_proc_unlock(proc);
                thread->return_error.cmd = return_error;
                binder_enqueue_thread_work(thread, &thread->return_error.work);
        }
}

static int
binder_request_freeze_notification(struct binder_proc *proc,
                                   struct binder_thread *thread,
                                   struct binder_handle_cookie *handle_cookie)
{
        struct binder_ref_freeze *freeze;
        struct binder_ref *ref;

        freeze = kzalloc(sizeof(*freeze), GFP_KERNEL);
        if (!freeze)
                return -ENOMEM;
        binder_proc_lock(proc);
        ref = binder_get_ref_olocked(proc, handle_cookie->handle, false);
        if (!ref) {
                binder_user_error("%d:%d BC_REQUEST_FREEZE_NOTIFICATION invalid ref %d\n",
                                  proc->pid, thread->pid, handle_cookie->handle);
                binder_proc_unlock(proc);
                kfree(freeze);
                return -EINVAL;
        }

        binder_node_lock(ref->node);
        if (ref->freeze) {
                binder_user_error("%d:%d BC_REQUEST_FREEZE_NOTIFICATION already set\n",
                                  proc->pid, thread->pid);
                binder_node_unlock(ref->node);
                binder_proc_unlock(proc);
                kfree(freeze);
                return -EINVAL;
        }

        binder_stats_created(BINDER_STAT_FREEZE);
        INIT_LIST_HEAD(&freeze->work.entry);
        freeze->cookie = handle_cookie->cookie;
        freeze->work.type = BINDER_WORK_FROZEN_BINDER;
        ref->freeze = freeze;

        if (ref->node->proc) {
                binder_inner_proc_lock(ref->node->proc);
                freeze->is_frozen = ref->node->proc->is_frozen;
                binder_inner_proc_unlock(ref->node->proc);

                binder_inner_proc_lock(proc);
                binder_enqueue_work_ilocked(&freeze->work, &proc->todo);
                binder_wakeup_proc_ilocked(proc);
                binder_inner_proc_unlock(proc);
        }

        binder_node_unlock(ref->node);
        binder_proc_unlock(proc);
        return 0;
}

static int
binder_clear_freeze_notification(struct binder_proc *proc,
                                 struct binder_thread *thread,
                                 struct binder_handle_cookie *handle_cookie)
{
        struct binder_ref_freeze *freeze;
        struct binder_ref *ref;

        binder_proc_lock(proc);
        ref = binder_get_ref_olocked(proc, handle_cookie->handle, false);
        if (!ref) {
                binder_user_error("%d:%d BC_CLEAR_FREEZE_NOTIFICATION invalid ref %d\n",
                                  proc->pid, thread->pid, handle_cookie->handle);
                binder_proc_unlock(proc);
                return -EINVAL;
        }

        binder_node_lock(ref->node);

        if (!ref->freeze) {
                binder_user_error("%d:%d BC_CLEAR_FREEZE_NOTIFICATION freeze notification not active\n",
                                  proc->pid, thread->pid);
                binder_node_unlock(ref->node);
                binder_proc_unlock(proc);
                return -EINVAL;
        }
        freeze = ref->freeze;
        binder_inner_proc_lock(proc);
        if (freeze->cookie != handle_cookie->cookie) {
                binder_user_error("%d:%d BC_CLEAR_FREEZE_NOTIFICATION freeze notification cookie mismatch %016llx != %016llx\n",
                                  proc->pid, thread->pid, (u64)freeze->cookie,
                                  (u64)handle_cookie->cookie);
                binder_inner_proc_unlock(proc);
                binder_node_unlock(ref->node);
                binder_proc_unlock(proc);
                return -EINVAL;
        }
        ref->freeze = NULL;
        /*
         * Take the existing freeze object and overwrite its work type. There are three cases here:
         * 1. No pending notification. In this case just add the work to the queue.
         * 2. A notification was sent and is pending an ack from userspace. Once an ack arrives, we
         *    should resend with the new work type.
         * 3. A notification is pending to be sent. Since the work is already in the queue, nothing
         *    needs to be done here.
         */
        freeze->work.type = BINDER_WORK_CLEAR_FREEZE_NOTIFICATION;
        if (list_empty(&freeze->work.entry)) {
                binder_enqueue_work_ilocked(&freeze->work, &proc->todo);
                binder_wakeup_proc_ilocked(proc);
        } else if (freeze->sent) {
                freeze->resend = true;
        }
        binder_inner_proc_unlock(proc);
        binder_node_unlock(ref->node);
        binder_proc_unlock(proc);
        return 0;
}

static int
binder_freeze_notification_done(struct binder_proc *proc,
                                struct binder_thread *thread,
                                binder_uintptr_t cookie)
{
        struct binder_ref_freeze *freeze = NULL;
        struct binder_work *w;

        binder_inner_proc_lock(proc);
        list_for_each_entry(w, &proc->delivered_freeze, entry) {
                struct binder_ref_freeze *tmp_freeze =
                        container_of(w, struct binder_ref_freeze, work);

                if (tmp_freeze->cookie == cookie) {
                        freeze = tmp_freeze;
                        break;
                }
        }
        if (!freeze) {
                binder_user_error("%d:%d BC_FREEZE_NOTIFICATION_DONE %016llx not found\n",
                                  proc->pid, thread->pid, (u64)cookie);
                binder_inner_proc_unlock(proc);
                return -EINVAL;
        }
        binder_dequeue_work_ilocked(&freeze->work);
        freeze->sent = false;
        if (freeze->resend) {
                freeze->resend = false;
                binder_enqueue_work_ilocked(&freeze->work, &proc->todo);
                binder_wakeup_proc_ilocked(proc);
        }
        binder_inner_proc_unlock(proc);
        return 0;
}

/**
 * binder_free_buf() - free the specified buffer
 * @proc:       binder proc that owns buffer
 * @buffer:     buffer to be freed
 * @is_failure: failed to send transaction
 *
 * If buffer for an async transaction, enqueue the next async
 * transaction from the node.
 *
 * Cleanup buffer and free it.
 */
static void
binder_free_buf(struct binder_proc *proc,
                struct binder_thread *thread,
                struct binder_buffer *buffer, bool is_failure)
{
        binder_inner_proc_lock(proc);
        if (buffer->transaction) {
                buffer->transaction->buffer = NULL;
                buffer->transaction = NULL;
        }
        binder_inner_proc_unlock(proc);
        if (buffer->async_transaction && buffer->target_node) {
                struct binder_node *buf_node;
                struct binder_work *w;

                buf_node = buffer->target_node;
                binder_node_inner_lock(buf_node);
                BUG_ON(!buf_node->has_async_transaction);
                BUG_ON(buf_node->proc != proc);
                w = binder_dequeue_work_head_ilocked(
                                &buf_node->async_todo);
                if (!w) {
                        buf_node->has_async_transaction = false;
                } else {
                        binder_enqueue_work_ilocked(
                                        w, &proc->todo);
                        binder_wakeup_proc_ilocked(proc);
                }
                binder_node_inner_unlock(buf_node);
        }
        trace_binder_transaction_buffer_release(buffer);
        binder_release_entire_buffer(proc, thread, buffer, is_failure);
        binder_alloc_free_buf(&proc->alloc, buffer);
}

static int binder_thread_write(struct binder_proc *proc,
                        struct binder_thread *thread,
                        binder_uintptr_t binder_buffer, size_t size,
                        binder_size_t *consumed)
{
        uint32_t cmd;
        struct binder_context *context = proc->context;
        void __user *buffer = (void __user *)(uintptr_t)binder_buffer;
        void __user *ptr = buffer + *consumed;
        void __user *end = buffer + size;

        while (ptr < end && thread->return_error.cmd == BR_OK) {
                int ret;

                if (get_user(cmd, (uint32_t __user *)ptr))
                        return -EFAULT;
                ptr += sizeof(uint32_t);
                trace_binder_command(cmd);
                if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.bc)) {
                        atomic_inc(&binder_stats.bc[_IOC_NR(cmd)]);
                        atomic_inc(&proc->stats.bc[_IOC_NR(cmd)]);
                        atomic_inc(&thread->stats.bc[_IOC_NR(cmd)]);
                }
                switch (cmd) {
                case BC_INCREFS:
                case BC_ACQUIRE:
                case BC_RELEASE:
                case BC_DECREFS: {
                        uint32_t target;
                        const char *debug_string;
                        bool strong = cmd == BC_ACQUIRE || cmd == BC_RELEASE;
                        bool increment = cmd == BC_INCREFS || cmd == BC_ACQUIRE;
                        struct binder_ref_data rdata;

                        if (get_user(target, (uint32_t __user *)ptr))
                                return -EFAULT;

                        ptr += sizeof(uint32_t);
                        ret = -1;
                        if (increment && !target) {
                                struct binder_node *ctx_mgr_node;

                                mutex_lock(&context->context_mgr_node_lock);
                                ctx_mgr_node = context->binder_context_mgr_node;
                                if (ctx_mgr_node) {
                                        if (ctx_mgr_node->proc == proc) {
                                                binder_user_error("%d:%d context manager tried to acquire desc 0\n",
                                                                  proc->pid, thread->pid);
                                                mutex_unlock(&context->context_mgr_node_lock);
                                                return -EINVAL;
                                        }
                                        ret = binder_inc_ref_for_node(
                                                        proc, ctx_mgr_node,
                                                        strong, NULL, &rdata);
                                }
                                mutex_unlock(&context->context_mgr_node_lock);
                        }
                        if (ret)
                                ret = binder_update_ref_for_handle(
                                                proc, target, increment, strong,
                                                &rdata);
                        if (!ret && rdata.desc != target) {
                                binder_user_error("%d:%d tried to acquire reference to desc %d, got %d instead\n",
                                        proc->pid, thread->pid,
                                        target, rdata.desc);
                        }
                        switch (cmd) {
                        case BC_INCREFS:
                                debug_string = "IncRefs";
                                break;
                        case BC_ACQUIRE:
                                debug_string = "Acquire";
                                break;
                        case BC_RELEASE:
                                debug_string = "Release";
                                break;
                        case BC_DECREFS:
                        default:
                                debug_string = "DecRefs";
                                break;
                        }
                        if (ret) {
                                binder_user_error("%d:%d %s %d refcount change on invalid ref %d ret %d\n",
                                        proc->pid, thread->pid, debug_string,
                                        strong, target, ret);
                                break;
                        }
                        binder_debug(BINDER_DEBUG_USER_REFS,
                                     "%d:%d %s ref %d desc %d s %d w %d\n",
                                     proc->pid, thread->pid, debug_string,
                                     rdata.debug_id, rdata.desc, rdata.strong,
                                     rdata.weak);
                        break;
                }
                case BC_INCREFS_DONE:
                case BC_ACQUIRE_DONE: {
                        binder_uintptr_t node_ptr;
                        binder_uintptr_t cookie;
                        struct binder_node *node;
                        bool free_node;

                        if (get_user(node_ptr, (binder_uintptr_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(binder_uintptr_t);
                        if (get_user(cookie, (binder_uintptr_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(binder_uintptr_t);
                        node = binder_get_node(proc, node_ptr);
                        if (node == NULL) {
                                binder_user_error("%d:%d %s u%016llx no match\n",
                                        proc->pid, thread->pid,
                                        cmd == BC_INCREFS_DONE ?
                                        "BC_INCREFS_DONE" :
                                        "BC_ACQUIRE_DONE",
                                        (u64)node_ptr);
                                break;
                        }
                        if (cookie != node->cookie) {
                                binder_user_error("%d:%d %s u%016llx node %d cookie mismatch %016llx != %016llx\n",
                                        proc->pid, thread->pid,
                                        cmd == BC_INCREFS_DONE ?
                                        "BC_INCREFS_DONE" : "BC_ACQUIRE_DONE",
                                        (u64)node_ptr, node->debug_id,
                                        (u64)cookie, (u64)node->cookie);
                                binder_put_node(node);
                                break;
                        }
                        binder_node_inner_lock(node);
                        if (cmd == BC_ACQUIRE_DONE) {
                                if (node->pending_strong_ref == 0) {
                                        binder_user_error("%d:%d BC_ACQUIRE_DONE node %d has no pending acquire request\n",
                                                proc->pid, thread->pid,
                                                node->debug_id);
                                        binder_node_inner_unlock(node);
                                        binder_put_node(node);
                                        break;
                                }
                                node->pending_strong_ref = 0;
                        } else {
                                if (node->pending_weak_ref == 0) {
                                        binder_user_error("%d:%d BC_INCREFS_DONE node %d has no pending increfs request\n",
                                                proc->pid, thread->pid,
                                                node->debug_id);
                                        binder_node_inner_unlock(node);
                                        binder_put_node(node);
                                        break;
                                }
                                node->pending_weak_ref = 0;
                        }
                        free_node = binder_dec_node_nilocked(node,
                                        cmd == BC_ACQUIRE_DONE, 0);
                        WARN_ON(free_node);
                        binder_debug(BINDER_DEBUG_USER_REFS,
                                     "%d:%d %s node %d ls %d lw %d tr %d\n",
                                     proc->pid, thread->pid,
                                     cmd == BC_INCREFS_DONE ? "BC_INCREFS_DONE" : "BC_ACQUIRE_DONE",
                                     node->debug_id, node->local_strong_refs,
                                     node->local_weak_refs, node->tmp_refs);
                        binder_node_inner_unlock(node);
                        binder_put_node(node);
                        break;
                }
                case BC_ATTEMPT_ACQUIRE:
                        pr_err("BC_ATTEMPT_ACQUIRE not supported\n");
                        return -EINVAL;
                case BC_ACQUIRE_RESULT:
                        pr_err("BC_ACQUIRE_RESULT not supported\n");
                        return -EINVAL;

                case BC_FREE_BUFFER: {
                        binder_uintptr_t data_ptr;
                        struct binder_buffer *buffer;

                        if (get_user(data_ptr, (binder_uintptr_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(binder_uintptr_t);

                        buffer = binder_alloc_prepare_to_free(&proc->alloc,
                                                              data_ptr);
                        if (IS_ERR_OR_NULL(buffer)) {
                                if (PTR_ERR(buffer) == -EPERM) {
                                        binder_user_error(
                                                "%d:%d BC_FREE_BUFFER u%016llx matched unreturned or currently freeing buffer\n",
                                                proc->pid, thread->pid,
                                                (u64)data_ptr);
                                } else {
                                        binder_user_error(
                                                "%d:%d BC_FREE_BUFFER u%016llx no match\n",
                                                proc->pid, thread->pid,
                                                (u64)data_ptr);
                                }
                                break;
                        }
                        binder_debug(BINDER_DEBUG_FREE_BUFFER,
                                     "%d:%d BC_FREE_BUFFER u%016llx found buffer %d for %s transaction\n",
                                     proc->pid, thread->pid, (u64)data_ptr,
                                     buffer->debug_id,
                                     buffer->transaction ? "active" : "finished");
                        binder_free_buf(proc, thread, buffer, false);
                        break;
                }

                case BC_TRANSACTION_SG:
                case BC_REPLY_SG: {
                        struct binder_transaction_data_sg tr;

                        if (copy_from_user(&tr, ptr, sizeof(tr)))
                                return -EFAULT;
                        ptr += sizeof(tr);
                        binder_transaction(proc, thread, &tr.transaction_data,
                                           cmd == BC_REPLY_SG, tr.buffers_size);
                        break;
                }
                case BC_TRANSACTION:
                case BC_REPLY: {
                        struct binder_transaction_data tr;

                        if (copy_from_user(&tr, ptr, sizeof(tr)))
                                return -EFAULT;
                        ptr += sizeof(tr);
                        binder_transaction(proc, thread, &tr,
                                           cmd == BC_REPLY, 0);
                        break;
                }

                case BC_REGISTER_LOOPER:
                        binder_debug(BINDER_DEBUG_THREADS,
                                     "%d:%d BC_REGISTER_LOOPER\n",
                                     proc->pid, thread->pid);
                        binder_inner_proc_lock(proc);
                        if (thread->looper & BINDER_LOOPER_STATE_ENTERED) {
                                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                                binder_user_error("%d:%d ERROR: BC_REGISTER_LOOPER called after BC_ENTER_LOOPER\n",
                                        proc->pid, thread->pid);
                        } else if (proc->requested_threads == 0) {
                                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                                binder_user_error("%d:%d ERROR: BC_REGISTER_LOOPER called without request\n",
                                        proc->pid, thread->pid);
                        } else {
                                proc->requested_threads--;
                                proc->requested_threads_started++;
                        }
                        thread->looper |= BINDER_LOOPER_STATE_REGISTERED;
                        binder_inner_proc_unlock(proc);
                        break;
                case BC_ENTER_LOOPER:
                        binder_debug(BINDER_DEBUG_THREADS,
                                     "%d:%d BC_ENTER_LOOPER\n",
                                     proc->pid, thread->pid);
                        if (thread->looper & BINDER_LOOPER_STATE_REGISTERED) {
                                thread->looper |= BINDER_LOOPER_STATE_INVALID;
                                binder_user_error("%d:%d ERROR: BC_ENTER_LOOPER called after BC_REGISTER_LOOPER\n",
                                        proc->pid, thread->pid);
                        }
                        thread->looper |= BINDER_LOOPER_STATE_ENTERED;
                        break;
                case BC_EXIT_LOOPER:
                        binder_debug(BINDER_DEBUG_THREADS,
                                     "%d:%d BC_EXIT_LOOPER\n",
                                     proc->pid, thread->pid);
                        thread->looper |= BINDER_LOOPER_STATE_EXITED;
                        break;

                case BC_REQUEST_DEATH_NOTIFICATION:
                case BC_CLEAR_DEATH_NOTIFICATION: {
                        uint32_t target;
                        binder_uintptr_t cookie;
                        struct binder_ref *ref;
                        struct binder_ref_death *death = NULL;

                        if (get_user(target, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        if (get_user(cookie, (binder_uintptr_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(binder_uintptr_t);
                        if (cmd == BC_REQUEST_DEATH_NOTIFICATION) {
                                /*
                                 * Allocate memory for death notification
                                 * before taking lock
                                 */
                                death = kzalloc(sizeof(*death), GFP_KERNEL);
                                if (death == NULL) {
                                        WARN_ON(thread->return_error.cmd !=
                                                BR_OK);
                                        thread->return_error.cmd = BR_ERROR;
                                        binder_enqueue_thread_work(
                                                thread,
                                                &thread->return_error.work);
                                        binder_debug(
                                                BINDER_DEBUG_FAILED_TRANSACTION,
                                                "%d:%d BC_REQUEST_DEATH_NOTIFICATION failed\n",
                                                proc->pid, thread->pid);
                                        break;
                                }
                        }
                        binder_proc_lock(proc);
                        ref = binder_get_ref_olocked(proc, target, false);
                        if (ref == NULL) {
                                binder_user_error("%d:%d %s invalid ref %d\n",
                                        proc->pid, thread->pid,
                                        cmd == BC_REQUEST_DEATH_NOTIFICATION ?
                                        "BC_REQUEST_DEATH_NOTIFICATION" :
                                        "BC_CLEAR_DEATH_NOTIFICATION",
                                        target);
                                binder_proc_unlock(proc);
                                kfree(death);
                                break;
                        }

                        binder_debug(BINDER_DEBUG_DEATH_NOTIFICATION,
                                     "%d:%d %s %016llx ref %d desc %d s %d w %d for node %d\n",
                                     proc->pid, thread->pid,
                                     cmd == BC_REQUEST_DEATH_NOTIFICATION ?
                                     "BC_REQUEST_DEATH_NOTIFICATION" :
                                     "BC_CLEAR_DEATH_NOTIFICATION",
                                     (u64)cookie, ref->data.debug_id,
                                     ref->data.desc, ref->data.strong,
                                     ref->data.weak, ref->node->debug_id);

                        binder_node_lock(ref->node);
                        if (cmd == BC_REQUEST_DEATH_NOTIFICATION) {
                                if (ref->death) {
                                        binder_user_error("%d:%d BC_REQUEST_DEATH_NOTIFICATION death notification already set\n",
                                                proc->pid, thread->pid);
                                        binder_node_unlock(ref->node);
                                        binder_proc_unlock(proc);
                                        kfree(death);
                                        break;
                                }
                                binder_stats_created(BINDER_STAT_DEATH);
                                INIT_LIST_HEAD(&death->work.entry);
                                death->cookie = cookie;
                                ref->death = death;
                                if (ref->node->proc == NULL) {
                                        ref->death->work.type = BINDER_WORK_DEAD_BINDER;

                                        binder_inner_proc_lock(proc);
                                        binder_enqueue_work_ilocked(
                                                &ref->death->work, &proc->todo);
                                        binder_wakeup_proc_ilocked(proc);
                                        binder_inner_proc_unlock(proc);
                                }
                        } else {
                                if (ref->death == NULL) {
                                        binder_user_error("%d:%d BC_CLEAR_DEATH_NOTIFICATION death notification not active\n",
                                                proc->pid, thread->pid);
                                        binder_node_unlock(ref->node);
                                        binder_proc_unlock(proc);
                                        break;
                                }
                                death = ref->death;
                                if (death->cookie != cookie) {
                                        binder_user_error("%d:%d BC_CLEAR_DEATH_NOTIFICATION death notification cookie mismatch %016llx != %016llx\n",
                                                proc->pid, thread->pid,
                                                (u64)death->cookie,
                                                (u64)cookie);
                                        binder_node_unlock(ref->node);
                                        binder_proc_unlock(proc);
                                        break;
                                }
                                ref->death = NULL;
                                binder_inner_proc_lock(proc);
                                if (list_empty(&death->work.entry)) {
                                        death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
                                        if (thread->looper &
                                            (BINDER_LOOPER_STATE_REGISTERED |
                                             BINDER_LOOPER_STATE_ENTERED))
                                                binder_enqueue_thread_work_ilocked(
                                                                thread,
                                                                &death->work);
                                        else {
                                                binder_enqueue_work_ilocked(
                                                                &death->work,
                                                                &proc->todo);
                                                binder_wakeup_proc_ilocked(
                                                                proc);
                                        }
                                } else {
                                        BUG_ON(death->work.type != BINDER_WORK_DEAD_BINDER);
                                        death->work.type = BINDER_WORK_DEAD_BINDER_AND_CLEAR;
                                }
                                binder_inner_proc_unlock(proc);
                        }
                        binder_node_unlock(ref->node);
                        binder_proc_unlock(proc);
                } break;
                case BC_DEAD_BINDER_DONE: {
                        struct binder_work *w;
                        binder_uintptr_t cookie;
                        struct binder_ref_death *death = NULL;

                        if (get_user(cookie, (binder_uintptr_t __user *)ptr))
                                return -EFAULT;

                        ptr += sizeof(cookie);
                        binder_inner_proc_lock(proc);
                        list_for_each_entry(w, &proc->delivered_death,
                                            entry) {
                                struct binder_ref_death *tmp_death =
                                        container_of(w,
                                                     struct binder_ref_death,
                                                     work);

                                if (tmp_death->cookie == cookie) {
                                        death = tmp_death;
                                        break;
                                }
                        }
                        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                                     "%d:%d BC_DEAD_BINDER_DONE %016llx found %pK\n",
                                     proc->pid, thread->pid, (u64)cookie,
                                     death);
                        if (death == NULL) {
                                binder_user_error("%d:%d BC_DEAD_BINDER_DONE %016llx not found\n",
                                        proc->pid, thread->pid, (u64)cookie);
                                binder_inner_proc_unlock(proc);
                                break;
                        }
                        binder_dequeue_work_ilocked(&death->work);
                        if (death->work.type == BINDER_WORK_DEAD_BINDER_AND_CLEAR) {
                                death->work.type = BINDER_WORK_CLEAR_DEATH_NOTIFICATION;
                                if (thread->looper &
                                        (BINDER_LOOPER_STATE_REGISTERED |
                                         BINDER_LOOPER_STATE_ENTERED))
                                        binder_enqueue_thread_work_ilocked(
                                                thread, &death->work);
                                else {
                                        binder_enqueue_work_ilocked(
                                                        &death->work,
                                                        &proc->todo);
                                        binder_wakeup_proc_ilocked(proc);
                                }
                        }
                        binder_inner_proc_unlock(proc);
                } break;

                case BC_REQUEST_FREEZE_NOTIFICATION: {
                        struct binder_handle_cookie handle_cookie;
                        int error;

                        if (copy_from_user(&handle_cookie, ptr, sizeof(handle_cookie)))
                                return -EFAULT;
                        ptr += sizeof(handle_cookie);
                        error = binder_request_freeze_notification(proc, thread,
                                                                   &handle_cookie);
                        if (error)
                                return error;
                } break;

                case BC_CLEAR_FREEZE_NOTIFICATION: {
                        struct binder_handle_cookie handle_cookie;
                        int error;

                        if (copy_from_user(&handle_cookie, ptr, sizeof(handle_cookie)))
                                return -EFAULT;
                        ptr += sizeof(handle_cookie);
                        error = binder_clear_freeze_notification(proc, thread, &handle_cookie);
                        if (error)
                                return error;
                } break;

                case BC_FREEZE_NOTIFICATION_DONE: {
                        binder_uintptr_t cookie;
                        int error;

                        if (get_user(cookie, (binder_uintptr_t __user *)ptr))
                                return -EFAULT;

                        ptr += sizeof(cookie);
                        error = binder_freeze_notification_done(proc, thread, cookie);
                        if (error)
                                return error;
                } break;

                default:
                        pr_err("%d:%d unknown command %u\n",
                               proc->pid, thread->pid, cmd);
                        return -EINVAL;
                }
                *consumed = ptr - buffer;
        }
        return 0;
}

static void binder_stat_br(struct binder_proc *proc,
                           struct binder_thread *thread, uint32_t cmd)
{
        trace_binder_return(cmd);
        if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.br)) {
                atomic_inc(&binder_stats.br[_IOC_NR(cmd)]);
                atomic_inc(&proc->stats.br[_IOC_NR(cmd)]);
                atomic_inc(&thread->stats.br[_IOC_NR(cmd)]);
        }
}

static int binder_put_node_cmd(struct binder_proc *proc,
                               struct binder_thread *thread,
                               void __user **ptrp,
                               binder_uintptr_t node_ptr,
                               binder_uintptr_t node_cookie,
                               int node_debug_id,
                               uint32_t cmd, const char *cmd_name)
{
        void __user *ptr = *ptrp;

        if (put_user(cmd, (uint32_t __user *)ptr))
                return -EFAULT;
        ptr += sizeof(uint32_t);

        if (put_user(node_ptr, (binder_uintptr_t __user *)ptr))
                return -EFAULT;
        ptr += sizeof(binder_uintptr_t);

        if (put_user(node_cookie, (binder_uintptr_t __user *)ptr))
                return -EFAULT;
        ptr += sizeof(binder_uintptr_t);

        binder_stat_br(proc, thread, cmd);
        binder_debug(BINDER_DEBUG_USER_REFS, "%d:%d %s %d u%016llx c%016llx\n",
                     proc->pid, thread->pid, cmd_name, node_debug_id,
                     (u64)node_ptr, (u64)node_cookie);

        *ptrp = ptr;
        return 0;
}

static int binder_wait_for_work(struct binder_thread *thread,
                                bool do_proc_work)
{
        DEFINE_WAIT(wait);
        struct binder_proc *proc = thread->proc;
        int ret = 0;

        binder_inner_proc_lock(proc);
        for (;;) {
                prepare_to_wait(&thread->wait, &wait, TASK_INTERRUPTIBLE|TASK_FREEZABLE);
                if (binder_has_work_ilocked(thread, do_proc_work))
                        break;
                if (do_proc_work)
                        list_add(&thread->waiting_thread_node,
                                 &proc->waiting_threads);
                binder_inner_proc_unlock(proc);
                schedule();
                binder_inner_proc_lock(proc);
                list_del_init(&thread->waiting_thread_node);
                if (signal_pending(current)) {
                        ret = -EINTR;
                        break;
                }
        }
        finish_wait(&thread->wait, &wait);
        binder_inner_proc_unlock(proc);

        return ret;
}

/**
 * binder_apply_fd_fixups() - finish fd translation
 * @proc:         binder_proc associated @t->buffer
 * @t:  binder transaction with list of fd fixups
 *
 * Now that we are in the context of the transaction target
 * process, we can allocate and install fds. Process the
 * list of fds to translate and fixup the buffer with the
 * new fds first and only then install the files.
 *
 * If we fail to allocate an fd, skip the install and release
 * any fds that have already been allocated.
 */
static int binder_apply_fd_fixups(struct binder_proc *proc,
                                  struct binder_transaction *t)
{
        struct binder_txn_fd_fixup *fixup, *tmp;
        int ret = 0;

        list_for_each_entry(fixup, &t->fd_fixups, fixup_entry) {
                int fd = get_unused_fd_flags(O_CLOEXEC);

                if (fd < 0) {
                        binder_debug(BINDER_DEBUG_TRANSACTION,
                                     "failed fd fixup txn %d fd %d\n",
                                     t->debug_id, fd);
                        ret = -ENOMEM;
                        goto err;
                }
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "fd fixup txn %d fd %d\n",
                             t->debug_id, fd);
                trace_binder_transaction_fd_recv(t, fd, fixup->offset);
                fixup->target_fd = fd;
                if (binder_alloc_copy_to_buffer(&proc->alloc, t->buffer,
                                                fixup->offset, &fd,
                                                sizeof(u32))) {
                        ret = -EINVAL;
                        goto err;
                }
        }
        list_for_each_entry_safe(fixup, tmp, &t->fd_fixups, fixup_entry) {
                fd_install(fixup->target_fd, fixup->file);
                list_del(&fixup->fixup_entry);
                kfree(fixup);
        }

        return ret;

err:
        binder_free_txn_fixups(t);
        return ret;
}

static int binder_thread_read(struct binder_proc *proc,
                              struct binder_thread *thread,
                              binder_uintptr_t binder_buffer, size_t size,
                              binder_size_t *consumed, int non_block)
{
        void __user *buffer = (void __user *)(uintptr_t)binder_buffer;
        void __user *ptr = buffer + *consumed;
        void __user *end = buffer + size;

        int ret = 0;
        int wait_for_proc_work;

        if (*consumed == 0) {
                if (put_user(BR_NOOP, (uint32_t __user *)ptr))
                        return -EFAULT;
                ptr += sizeof(uint32_t);
        }

retry:
        binder_inner_proc_lock(proc);
        wait_for_proc_work = binder_available_for_proc_work_ilocked(thread);
        binder_inner_proc_unlock(proc);

        thread->looper |= BINDER_LOOPER_STATE_WAITING;

        trace_binder_wait_for_work(wait_for_proc_work,
                                   !!thread->transaction_stack,
                                   !binder_worklist_empty(proc, &thread->todo));
        if (wait_for_proc_work) {
                if (!(thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
                                        BINDER_LOOPER_STATE_ENTERED))) {
                        binder_user_error("%d:%d ERROR: Thread waiting for process work before calling BC_REGISTER_LOOPER or BC_ENTER_LOOPER (state %x)\n",
                                proc->pid, thread->pid, thread->looper);
                        wait_event_interruptible(binder_user_error_wait,
                                                 binder_stop_on_user_error < 2);
                }
                binder_set_nice(proc->default_priority);
        }

        if (non_block) {
                if (!binder_has_work(thread, wait_for_proc_work))
                        ret = -EAGAIN;
        } else {
                ret = binder_wait_for_work(thread, wait_for_proc_work);
        }

        thread->looper &= ~BINDER_LOOPER_STATE_WAITING;

        if (ret)
                return ret;

        while (1) {
                uint32_t cmd;
                struct binder_transaction_data_secctx tr;
                struct binder_transaction_data *trd = &tr.transaction_data;
                struct binder_work *w = NULL;
                struct list_head *list = NULL;
                struct binder_transaction *t = NULL;
                struct binder_thread *t_from;
                size_t trsize = sizeof(*trd);

                binder_inner_proc_lock(proc);
                if (!binder_worklist_empty_ilocked(&thread->todo))
                        list = &thread->todo;
                else if (!binder_worklist_empty_ilocked(&proc->todo) &&
                           wait_for_proc_work)
                        list = &proc->todo;
                else {
                        binder_inner_proc_unlock(proc);

                        /* no data added */
                        if (ptr - buffer == 4 && !thread->looper_need_return)
                                goto retry;
                        break;
                }

                if (end - ptr < sizeof(tr) + 4) {
                        binder_inner_proc_unlock(proc);
                        break;
                }
                w = binder_dequeue_work_head_ilocked(list);
                if (binder_worklist_empty_ilocked(&thread->todo))
                        thread->process_todo = false;

                switch (w->type) {
                case BINDER_WORK_TRANSACTION: {
                        binder_inner_proc_unlock(proc);
                        t = container_of(w, struct binder_transaction, work);
                } break;
                case BINDER_WORK_RETURN_ERROR: {
                        struct binder_error *e = container_of(
                                        w, struct binder_error, work);

                        WARN_ON(e->cmd == BR_OK);
                        binder_inner_proc_unlock(proc);
                        if (put_user(e->cmd, (uint32_t __user *)ptr))
                                return -EFAULT;
                        cmd = e->cmd;
                        e->cmd = BR_OK;
                        ptr += sizeof(uint32_t);

                        binder_stat_br(proc, thread, cmd);
                } break;
                case BINDER_WORK_TRANSACTION_COMPLETE:
                case BINDER_WORK_TRANSACTION_PENDING:
                case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT: {
                        if (proc->oneway_spam_detection_enabled &&
                                   w->type == BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT)
                                cmd = BR_ONEWAY_SPAM_SUSPECT;
                        else if (w->type == BINDER_WORK_TRANSACTION_PENDING)
                                cmd = BR_TRANSACTION_PENDING_FROZEN;
                        else
                                cmd = BR_TRANSACTION_COMPLETE;
                        binder_inner_proc_unlock(proc);
                        kfree(w);
                        binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
                        if (put_user(cmd, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);

                        binder_stat_br(proc, thread, cmd);
                        binder_debug(BINDER_DEBUG_TRANSACTION_COMPLETE,
                                     "%d:%d BR_TRANSACTION_COMPLETE\n",
                                     proc->pid, thread->pid);
                } break;
                case BINDER_WORK_NODE: {
                        struct binder_node *node = container_of(w, struct binder_node, work);
                        int strong, weak;
                        binder_uintptr_t node_ptr = node->ptr;
                        binder_uintptr_t node_cookie = node->cookie;
                        int node_debug_id = node->debug_id;
                        int has_weak_ref;
                        int has_strong_ref;
                        void __user *orig_ptr = ptr;

                        BUG_ON(proc != node->proc);
                        strong = node->internal_strong_refs ||
                                        node->local_strong_refs;
                        weak = !hlist_empty(&node->refs) ||
                                        node->local_weak_refs ||
                                        node->tmp_refs || strong;
                        has_strong_ref = node->has_strong_ref;
                        has_weak_ref = node->has_weak_ref;

                        if (weak && !has_weak_ref) {
                                node->has_weak_ref = 1;
                                node->pending_weak_ref = 1;
                                node->local_weak_refs++;
                        }
                        if (strong && !has_strong_ref) {
                                node->has_strong_ref = 1;
                                node->pending_strong_ref = 1;
                                node->local_strong_refs++;
                        }
                        if (!strong && has_strong_ref)
                                node->has_strong_ref = 0;
                        if (!weak && has_weak_ref)
                                node->has_weak_ref = 0;
                        if (!weak && !strong) {
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "%d:%d node %d u%016llx c%016llx deleted\n",
                                             proc->pid, thread->pid,
                                             node_debug_id,
                                             (u64)node_ptr,
                                             (u64)node_cookie);
                                rb_erase(&node->rb_node, &proc->nodes);
                                binder_inner_proc_unlock(proc);
                                binder_node_lock(node);
                                /*
                                 * Acquire the node lock before freeing the
                                 * node to serialize with other threads that
                                 * may have been holding the node lock while
                                 * decrementing this node (avoids race where
                                 * this thread frees while the other thread
                                 * is unlocking the node after the final
                                 * decrement)
                                 */
                                binder_node_unlock(node);
                                binder_free_node(node);
                        } else
                                binder_inner_proc_unlock(proc);

                        if (weak && !has_weak_ref)
                                ret = binder_put_node_cmd(
                                                proc, thread, &ptr, node_ptr,
                                                node_cookie, node_debug_id,
                                                BR_INCREFS, "BR_INCREFS");
                        if (!ret && strong && !has_strong_ref)
                                ret = binder_put_node_cmd(
                                                proc, thread, &ptr, node_ptr,
                                                node_cookie, node_debug_id,
                                                BR_ACQUIRE, "BR_ACQUIRE");
                        if (!ret && !strong && has_strong_ref)
                                ret = binder_put_node_cmd(
                                                proc, thread, &ptr, node_ptr,
                                                node_cookie, node_debug_id,
                                                BR_RELEASE, "BR_RELEASE");
                        if (!ret && !weak && has_weak_ref)
                                ret = binder_put_node_cmd(
                                                proc, thread, &ptr, node_ptr,
                                                node_cookie, node_debug_id,
                                                BR_DECREFS, "BR_DECREFS");
                        if (orig_ptr == ptr)
                                binder_debug(BINDER_DEBUG_INTERNAL_REFS,
                                             "%d:%d node %d u%016llx c%016llx state unchanged\n",
                                             proc->pid, thread->pid,
                                             node_debug_id,
                                             (u64)node_ptr,
                                             (u64)node_cookie);
                        if (ret)
                                return ret;
                } break;
                case BINDER_WORK_DEAD_BINDER:
                case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
                case BINDER_WORK_CLEAR_DEATH_NOTIFICATION: {
                        struct binder_ref_death *death;
                        uint32_t cmd;
                        binder_uintptr_t cookie;

                        death = container_of(w, struct binder_ref_death, work);
                        if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION)
                                cmd = BR_CLEAR_DEATH_NOTIFICATION_DONE;
                        else
                                cmd = BR_DEAD_BINDER;
                        cookie = death->cookie;

                        binder_debug(BINDER_DEBUG_DEATH_NOTIFICATION,
                                     "%d:%d %s %016llx\n",
                                      proc->pid, thread->pid,
                                      cmd == BR_DEAD_BINDER ?
                                      "BR_DEAD_BINDER" :
                                      "BR_CLEAR_DEATH_NOTIFICATION_DONE",
                                      (u64)cookie);
                        if (w->type == BINDER_WORK_CLEAR_DEATH_NOTIFICATION) {
                                binder_inner_proc_unlock(proc);
                                kfree(death);
                                binder_stats_deleted(BINDER_STAT_DEATH);
                        } else {
                                binder_enqueue_work_ilocked(
                                                w, &proc->delivered_death);
                                binder_inner_proc_unlock(proc);
                        }
                        if (put_user(cmd, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        if (put_user(cookie,
                                     (binder_uintptr_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(binder_uintptr_t);
                        binder_stat_br(proc, thread, cmd);
                        if (cmd == BR_DEAD_BINDER)
                                goto done; /* DEAD_BINDER notifications can cause transactions */
                } break;

                case BINDER_WORK_FROZEN_BINDER: {
                        struct binder_ref_freeze *freeze;
                        struct binder_frozen_state_info info;

                        memset(&info, 0, sizeof(info));
                        freeze = container_of(w, struct binder_ref_freeze, work);
                        info.is_frozen = freeze->is_frozen;
                        info.cookie = freeze->cookie;
                        freeze->sent = true;
                        binder_enqueue_work_ilocked(w, &proc->delivered_freeze);
                        binder_inner_proc_unlock(proc);

                        if (put_user(BR_FROZEN_BINDER, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        if (copy_to_user(ptr, &info, sizeof(info)))
                                return -EFAULT;
                        ptr += sizeof(info);
                        binder_stat_br(proc, thread, BR_FROZEN_BINDER);
                        goto done; /* BR_FROZEN_BINDER notifications can cause transactions */
                } break;

                case BINDER_WORK_CLEAR_FREEZE_NOTIFICATION: {
                        struct binder_ref_freeze *freeze =
                            container_of(w, struct binder_ref_freeze, work);
                        binder_uintptr_t cookie = freeze->cookie;

                        binder_inner_proc_unlock(proc);
                        kfree(freeze);
                        binder_stats_deleted(BINDER_STAT_FREEZE);
                        if (put_user(BR_CLEAR_FREEZE_NOTIFICATION_DONE, (uint32_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(uint32_t);
                        if (put_user(cookie, (binder_uintptr_t __user *)ptr))
                                return -EFAULT;
                        ptr += sizeof(binder_uintptr_t);
                        binder_stat_br(proc, thread, BR_CLEAR_FREEZE_NOTIFICATION_DONE);
                } break;

                default:
                        binder_inner_proc_unlock(proc);
                        pr_err("%d:%d: bad work type %d\n",
                               proc->pid, thread->pid, w->type);
                        break;
                }

                if (!t)
                        continue;

                BUG_ON(t->buffer == NULL);
                if (t->buffer->target_node) {
                        struct binder_node *target_node = t->buffer->target_node;

                        trd->target.ptr = target_node->ptr;
                        trd->cookie =  target_node->cookie;
                        t->saved_priority = task_nice(current);
                        if (t->priority < target_node->min_priority &&
                            !(t->flags & TF_ONE_WAY))
                                binder_set_nice(t->priority);
                        else if (!(t->flags & TF_ONE_WAY) ||
                                 t->saved_priority > target_node->min_priority)
                                binder_set_nice(target_node->min_priority);
                        cmd = BR_TRANSACTION;
                } else {
                        trd->target.ptr = 0;
                        trd->cookie = 0;
                        cmd = BR_REPLY;
                }
                trd->code = t->code;
                trd->flags = t->flags;
                trd->sender_euid = from_kuid(current_user_ns(), t->sender_euid);

                t_from = binder_get_txn_from(t);
                if (t_from) {
                        struct task_struct *sender = t_from->proc->tsk;

                        trd->sender_pid =
                                task_tgid_nr_ns(sender,
                                                task_active_pid_ns(current));
                } else {
                        trd->sender_pid = 0;
                }

                ret = binder_apply_fd_fixups(proc, t);
                if (ret) {
                        struct binder_buffer *buffer = t->buffer;
                        bool oneway = !!(t->flags & TF_ONE_WAY);
                        int tid = t->debug_id;

                        if (t_from)
                                binder_thread_dec_tmpref(t_from);
                        buffer->transaction = NULL;
                        binder_cleanup_transaction(t, "fd fixups failed",
                                                   BR_FAILED_REPLY);
                        binder_free_buf(proc, thread, buffer, true);
                        binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
                                     "%d:%d %stransaction %d fd fixups failed %d/%d, line %d\n",
                                     proc->pid, thread->pid,
                                     oneway ? "async " :
                                        (cmd == BR_REPLY ? "reply " : ""),
                                     tid, BR_FAILED_REPLY, ret, __LINE__);
                        if (cmd == BR_REPLY) {
                                cmd = BR_FAILED_REPLY;
                                if (put_user(cmd, (uint32_t __user *)ptr))
                                        return -EFAULT;
                                ptr += sizeof(uint32_t);
                                binder_stat_br(proc, thread, cmd);
                                break;
                        }
                        continue;
                }
                trd->data_size = t->buffer->data_size;
                trd->offsets_size = t->buffer->offsets_size;
                trd->data.ptr.buffer = t->buffer->user_data;
                trd->data.ptr.offsets = trd->data.ptr.buffer +
                                        ALIGN(t->buffer->data_size,
                                            sizeof(void *));

                tr.secctx = t->security_ctx;
                if (t->security_ctx) {
                        cmd = BR_TRANSACTION_SEC_CTX;
                        trsize = sizeof(tr);
                }
                if (put_user(cmd, (uint32_t __user *)ptr)) {
                        if (t_from)
                                binder_thread_dec_tmpref(t_from);

                        binder_cleanup_transaction(t, "put_user failed",
                                                   BR_FAILED_REPLY);

                        return -EFAULT;
                }
                ptr += sizeof(uint32_t);
                if (copy_to_user(ptr, &tr, trsize)) {
                        if (t_from)
                                binder_thread_dec_tmpref(t_from);

                        binder_cleanup_transaction(t, "copy_to_user failed",
                                                   BR_FAILED_REPLY);

                        return -EFAULT;
                }
                ptr += trsize;

                trace_binder_transaction_received(t);
                binder_stat_br(proc, thread, cmd);
                binder_debug(BINDER_DEBUG_TRANSACTION,
                             "%d:%d %s %d %d:%d, cmd %u size %zd-%zd ptr %016llx-%016llx\n",
                             proc->pid, thread->pid,
                             (cmd == BR_TRANSACTION) ? "BR_TRANSACTION" :
                                (cmd == BR_TRANSACTION_SEC_CTX) ?
                                     "BR_TRANSACTION_SEC_CTX" : "BR_REPLY",
                             t->debug_id, t_from ? t_from->proc->pid : 0,
                             t_from ? t_from->pid : 0, cmd,
                             t->buffer->data_size, t->buffer->offsets_size,
                             (u64)trd->data.ptr.buffer,
                             (u64)trd->data.ptr.offsets);

                if (t_from)
                        binder_thread_dec_tmpref(t_from);
                t->buffer->allow_user_free = 1;
                if (cmd != BR_REPLY && !(t->flags & TF_ONE_WAY)) {
                        binder_inner_proc_lock(thread->proc);
                        t->to_parent = thread->transaction_stack;
                        t->to_thread = thread;
                        thread->transaction_stack = t;
                        binder_inner_proc_unlock(thread->proc);
                } else {
                        binder_free_transaction(t);
                }
                break;
        }

done:

        *consumed = ptr - buffer;
        binder_inner_proc_lock(proc);
        if (proc->requested_threads == 0 &&
            list_empty(&thread->proc->waiting_threads) &&
            proc->requested_threads_started < proc->max_threads &&
            (thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
             BINDER_LOOPER_STATE_ENTERED)) /* the user-space code fails to */
             /*spawn a new thread if we leave this out */) {
                proc->requested_threads++;
                binder_inner_proc_unlock(proc);
                binder_debug(BINDER_DEBUG_THREADS,
                             "%d:%d BR_SPAWN_LOOPER\n",
                             proc->pid, thread->pid);
                if (put_user(BR_SPAWN_LOOPER, (uint32_t __user *)buffer))
                        return -EFAULT;
                binder_stat_br(proc, thread, BR_SPAWN_LOOPER);
        } else
                binder_inner_proc_unlock(proc);
        return 0;
}

static void binder_release_work(struct binder_proc *proc,
                                struct list_head *list)
{
        struct binder_work *w;
        enum binder_work_type wtype;

        while (1) {
                binder_inner_proc_lock(proc);
                w = binder_dequeue_work_head_ilocked(list);
                wtype = w ? w->type : 0;
                binder_inner_proc_unlock(proc);
                if (!w)
                        return;

                switch (wtype) {
                case BINDER_WORK_TRANSACTION: {
                        struct binder_transaction *t;

                        t = container_of(w, struct binder_transaction, work);

                        binder_cleanup_transaction(t, "process died.",
                                                   BR_DEAD_REPLY);
                } break;
                case BINDER_WORK_RETURN_ERROR: {
                        struct binder_error *e = container_of(
                                        w, struct binder_error, work);

                        binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                                "undelivered TRANSACTION_ERROR: %u\n",
                                e->cmd);
                } break;
                case BINDER_WORK_TRANSACTION_PENDING:
                case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT:
                case BINDER_WORK_TRANSACTION_COMPLETE: {
                        binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                                "undelivered TRANSACTION_COMPLETE\n");
                        kfree(w);
                        binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
                } break;
                case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
                case BINDER_WORK_CLEAR_DEATH_NOTIFICATION: {
                        struct binder_ref_death *death;

                        death = container_of(w, struct binder_ref_death, work);
                        binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                                "undelivered death notification, %016llx\n",
                                (u64)death->cookie);
                        kfree(death);
                        binder_stats_deleted(BINDER_STAT_DEATH);
                } break;
                case BINDER_WORK_NODE:
                        break;
                case BINDER_WORK_CLEAR_FREEZE_NOTIFICATION: {
                        struct binder_ref_freeze *freeze;

                        freeze = container_of(w, struct binder_ref_freeze, work);
                        binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                                     "undelivered freeze notification, %016llx\n",
                                     (u64)freeze->cookie);
                        kfree(freeze);
                        binder_stats_deleted(BINDER_STAT_FREEZE);
                } break;
                default:
                        pr_err("unexpected work type, %d, not freed\n",
                               wtype);
                        break;
                }
        }

}

static struct binder_thread *binder_get_thread_ilocked(
                struct binder_proc *proc, struct binder_thread *new_thread)
{
        struct binder_thread *thread = NULL;
        struct rb_node *parent = NULL;
        struct rb_node **p = &proc->threads.rb_node;

        while (*p) {
                parent = *p;
                thread = rb_entry(parent, struct binder_thread, rb_node);

                if (current->pid < thread->pid)
                        p = &(*p)->rb_left;
                else if (current->pid > thread->pid)
                        p = &(*p)->rb_right;
                else
                        return thread;
        }
        if (!new_thread)
                return NULL;
        thread = new_thread;
        binder_stats_created(BINDER_STAT_THREAD);
        thread->proc = proc;
        thread->pid = current->pid;
        atomic_set(&thread->tmp_ref, 0);
        init_waitqueue_head(&thread->wait);
        INIT_LIST_HEAD(&thread->todo);
        rb_link_node(&thread->rb_node, parent, p);
        rb_insert_color(&thread->rb_node, &proc->threads);
        thread->looper_need_return = true;
        thread->return_error.work.type = BINDER_WORK_RETURN_ERROR;
        thread->return_error.cmd = BR_OK;
        thread->reply_error.work.type = BINDER_WORK_RETURN_ERROR;
        thread->reply_error.cmd = BR_OK;
        thread->ee.command = BR_OK;
        INIT_LIST_HEAD(&new_thread->waiting_thread_node);
        return thread;
}

static struct binder_thread *binder_get_thread(struct binder_proc *proc)
{
        struct binder_thread *thread;
        struct binder_thread *new_thread;

        binder_inner_proc_lock(proc);
        thread = binder_get_thread_ilocked(proc, NULL);
        binder_inner_proc_unlock(proc);
        if (!thread) {
                new_thread = kzalloc(sizeof(*thread), GFP_KERNEL);
                if (new_thread == NULL)
                        return NULL;
                binder_inner_proc_lock(proc);
                thread = binder_get_thread_ilocked(proc, new_thread);
                binder_inner_proc_unlock(proc);
                if (thread != new_thread)
                        kfree(new_thread);
        }
        return thread;
}

static void binder_free_proc(struct binder_proc *proc)
{
        struct binder_device *device;

        BUG_ON(!list_empty(&proc->todo));
        BUG_ON(!list_empty(&proc->delivered_death));
        if (proc->outstanding_txns)
                pr_warn("%s: Unexpected outstanding_txns %d\n",
                        __func__, proc->outstanding_txns);
        device = container_of(proc->context, struct binder_device, context);
        if (refcount_dec_and_test(&device->ref)) {
                kfree(proc->context->name);
                kfree(device);
        }
        binder_alloc_deferred_release(&proc->alloc);
        put_task_struct(proc->tsk);
        put_cred(proc->cred);
        binder_stats_deleted(BINDER_STAT_PROC);
        dbitmap_free(&proc->dmap);
        kfree(proc);
}

static void binder_free_thread(struct binder_thread *thread)
{
        BUG_ON(!list_empty(&thread->todo));
        binder_stats_deleted(BINDER_STAT_THREAD);
        binder_proc_dec_tmpref(thread->proc);
        kfree(thread);
}

static int binder_thread_release(struct binder_proc *proc,
                                 struct binder_thread *thread)
{
        struct binder_transaction *t;
        struct binder_transaction *send_reply = NULL;
        int active_transactions = 0;
        struct binder_transaction *last_t = NULL;

        binder_inner_proc_lock(thread->proc);
        /*
         * take a ref on the proc so it survives
         * after we remove this thread from proc->threads.
         * The corresponding dec is when we actually
         * free the thread in binder_free_thread()
         */
        proc->tmp_ref++;
        /*
         * take a ref on this thread to ensure it
         * survives while we are releasing it
         */
        atomic_inc(&thread->tmp_ref);
        rb_erase(&thread->rb_node, &proc->threads);
        t = thread->transaction_stack;
        if (t) {
                spin_lock(&t->lock);
                if (t->to_thread == thread)
                        send_reply = t;
        } else {
                __acquire(&t->lock);
        }
        thread->is_dead = true;

        while (t) {
                last_t = t;
                active_transactions++;
                binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
                             "release %d:%d transaction %d %s, still active\n",
                              proc->pid, thread->pid,
                             t->debug_id,
                             (t->to_thread == thread) ? "in" : "out");

                if (t->to_thread == thread) {
                        thread->proc->outstanding_txns--;
                        t->to_proc = NULL;
                        t->to_thread = NULL;
                        if (t->buffer) {
                                t->buffer->transaction = NULL;
                                t->buffer = NULL;
                        }
                        t = t->to_parent;
                } else if (t->from == thread) {
                        t->from = NULL;
                        t = t->from_parent;
                } else
                        BUG();
                spin_unlock(&last_t->lock);
                if (t)
                        spin_lock(&t->lock);
                else
                        __acquire(&t->lock);
        }
        /* annotation for sparse, lock not acquired in last iteration above */
        __release(&t->lock);

        /*
         * If this thread used poll, make sure we remove the waitqueue from any
         * poll data structures holding it.
         */
        if (thread->looper & BINDER_LOOPER_STATE_POLL)
                wake_up_pollfree(&thread->wait);

        binder_inner_proc_unlock(thread->proc);

        /*
         * This is needed to avoid races between wake_up_pollfree() above and
         * someone else removing the last entry from the queue for other reasons
         * (e.g. ep_remove_wait_queue() being called due to an epoll file
         * descriptor being closed).  Such other users hold an RCU read lock, so
         * we can be sure they're done after we call synchronize_rcu().
         */
        if (thread->looper & BINDER_LOOPER_STATE_POLL)
                synchronize_rcu();

        if (send_reply)
                binder_send_failed_reply(send_reply, BR_DEAD_REPLY);
        binder_release_work(proc, &thread->todo);
        binder_thread_dec_tmpref(thread);
        return active_transactions;
}

static __poll_t binder_poll(struct file *filp,
                                struct poll_table_struct *wait)
{
        struct binder_proc *proc = filp->private_data;
        struct binder_thread *thread = NULL;
        bool wait_for_proc_work;

        thread = binder_get_thread(proc);
        if (!thread)
                return EPOLLERR;

        binder_inner_proc_lock(thread->proc);
        thread->looper |= BINDER_LOOPER_STATE_POLL;
        wait_for_proc_work = binder_available_for_proc_work_ilocked(thread);

        binder_inner_proc_unlock(thread->proc);

        poll_wait(filp, &thread->wait, wait);

        if (binder_has_work(thread, wait_for_proc_work))
                return EPOLLIN;

        return 0;
}

static int binder_ioctl_write_read(struct file *filp, unsigned long arg,
                                struct binder_thread *thread)
{
        int ret = 0;
        struct binder_proc *proc = filp->private_data;
        void __user *ubuf = (void __user *)arg;
        struct binder_write_read bwr;

        if (copy_from_user(&bwr, ubuf, sizeof(bwr))) {
                ret = -EFAULT;
                goto out;
        }
        binder_debug(BINDER_DEBUG_READ_WRITE,
                     "%d:%d write %lld at %016llx, read %lld at %016llx\n",
                     proc->pid, thread->pid,
                     (u64)bwr.write_size, (u64)bwr.write_buffer,
                     (u64)bwr.read_size, (u64)bwr.read_buffer);

        if (bwr.write_size > 0) {
                ret = binder_thread_write(proc, thread,
                                          bwr.write_buffer,
                                          bwr.write_size,
                                          &bwr.write_consumed);
                trace_binder_write_done(ret);
                if (ret < 0) {
                        bwr.read_consumed = 0;
                        if (copy_to_user(ubuf, &bwr, sizeof(bwr)))
                                ret = -EFAULT;
                        goto out;
                }
        }
        if (bwr.read_size > 0) {
                ret = binder_thread_read(proc, thread, bwr.read_buffer,
                                         bwr.read_size,
                                         &bwr.read_consumed,
                                         filp->f_flags & O_NONBLOCK);
                trace_binder_read_done(ret);
                binder_inner_proc_lock(proc);
                if (!binder_worklist_empty_ilocked(&proc->todo))
                        binder_wakeup_proc_ilocked(proc);
                binder_inner_proc_unlock(proc);
                if (ret < 0) {
                        if (copy_to_user(ubuf, &bwr, sizeof(bwr)))
                                ret = -EFAULT;
                        goto out;
                }
        }
        binder_debug(BINDER_DEBUG_READ_WRITE,
                     "%d:%d wrote %lld of %lld, read return %lld of %lld\n",
                     proc->pid, thread->pid,
                     (u64)bwr.write_consumed, (u64)bwr.write_size,
                     (u64)bwr.read_consumed, (u64)bwr.read_size);
        if (copy_to_user(ubuf, &bwr, sizeof(bwr))) {
                ret = -EFAULT;
                goto out;
        }
out:
        return ret;
}

static int binder_ioctl_set_ctx_mgr(struct file *filp,
                                    struct flat_binder_object *fbo)
{
        int ret = 0;
        struct binder_proc *proc = filp->private_data;
        struct binder_context *context = proc->context;
        struct binder_node *new_node;
        kuid_t curr_euid = current_euid();

        mutex_lock(&context->context_mgr_node_lock);
        if (context->binder_context_mgr_node) {
                pr_err("BINDER_SET_CONTEXT_MGR already set\n");
                ret = -EBUSY;
                goto out;
        }
        ret = security_binder_set_context_mgr(proc->cred);
        if (ret < 0)
                goto out;
        if (uid_valid(context->binder_context_mgr_uid)) {
                if (!uid_eq(context->binder_context_mgr_uid, curr_euid)) {
                        pr_err("BINDER_SET_CONTEXT_MGR bad uid %d != %d\n",
                               from_kuid(&init_user_ns, curr_euid),
                               from_kuid(&init_user_ns,
                                         context->binder_context_mgr_uid));
                        ret = -EPERM;
                        goto out;
                }
        } else {
                context->binder_context_mgr_uid = curr_euid;
        }
        new_node = binder_new_node(proc, fbo);
        if (!new_node) {
                ret = -ENOMEM;
                goto out;
        }
        binder_node_lock(new_node);
        new_node->local_weak_refs++;
        new_node->local_strong_refs++;
        new_node->has_strong_ref = 1;
        new_node->has_weak_ref = 1;
        context->binder_context_mgr_node = new_node;
        binder_node_unlock(new_node);
        binder_put_node(new_node);
out:
        mutex_unlock(&context->context_mgr_node_lock);
        return ret;
}

static int binder_ioctl_get_node_info_for_ref(struct binder_proc *proc,
                struct binder_node_info_for_ref *info)
{
        struct binder_node *node;
        struct binder_context *context = proc->context;
        __u32 handle = info->handle;

        if (info->strong_count || info->weak_count || info->reserved1 ||
            info->reserved2 || info->reserved3) {
                binder_user_error("%d BINDER_GET_NODE_INFO_FOR_REF: only handle may be non-zero.",
                                  proc->pid);
                return -EINVAL;
        }

        /* This ioctl may only be used by the context manager */
        mutex_lock(&context->context_mgr_node_lock);
        if (!context->binder_context_mgr_node ||
                context->binder_context_mgr_node->proc != proc) {
                mutex_unlock(&context->context_mgr_node_lock);
                return -EPERM;
        }
        mutex_unlock(&context->context_mgr_node_lock);

        node = binder_get_node_from_ref(proc, handle, true, NULL);
        if (!node)
                return -EINVAL;

        info->strong_count = node->local_strong_refs +
                node->internal_strong_refs;
        info->weak_count = node->local_weak_refs;

        binder_put_node(node);

        return 0;
}

static int binder_ioctl_get_node_debug_info(struct binder_proc *proc,
                                struct binder_node_debug_info *info)
{
        struct rb_node *n;
        binder_uintptr_t ptr = info->ptr;

        memset(info, 0, sizeof(*info));

        binder_inner_proc_lock(proc);
        for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n)) {
                struct binder_node *node = rb_entry(n, struct binder_node,
                                                    rb_node);
                if (node->ptr > ptr) {
                        info->ptr = node->ptr;
                        info->cookie = node->cookie;
                        info->has_strong_ref = node->has_strong_ref;
                        info->has_weak_ref = node->has_weak_ref;
                        break;
                }
        }
        binder_inner_proc_unlock(proc);

        return 0;
}

static bool binder_txns_pending_ilocked(struct binder_proc *proc)
{
        struct rb_node *n;
        struct binder_thread *thread;

        if (proc->outstanding_txns > 0)
                return true;

        for (n = rb_first(&proc->threads); n; n = rb_next(n)) {
                thread = rb_entry(n, struct binder_thread, rb_node);
                if (thread->transaction_stack)
                        return true;
        }
        return false;
}

static void binder_add_freeze_work(struct binder_proc *proc, bool is_frozen)
{
        struct binder_node *prev = NULL;
        struct rb_node *n;
        struct binder_ref *ref;

        binder_inner_proc_lock(proc);
        for (n = rb_first(&proc->nodes); n; n = rb_next(n)) {
                struct binder_node *node;

                node = rb_entry(n, struct binder_node, rb_node);
                binder_inc_node_tmpref_ilocked(node);
                binder_inner_proc_unlock(proc);
                if (prev)
                        binder_put_node(prev);
                binder_node_lock(node);
                hlist_for_each_entry(ref, &node->refs, node_entry) {
                        /*
                         * Need the node lock to synchronize
                         * with new notification requests and the
                         * inner lock to synchronize with queued
                         * freeze notifications.
                         */
                        binder_inner_proc_lock(ref->proc);
                        if (!ref->freeze) {
                                binder_inner_proc_unlock(ref->proc);
                                continue;
                        }
                        ref->freeze->work.type = BINDER_WORK_FROZEN_BINDER;
                        if (list_empty(&ref->freeze->work.entry)) {
                                ref->freeze->is_frozen = is_frozen;
                                binder_enqueue_work_ilocked(&ref->freeze->work, &ref->proc->todo);
                                binder_wakeup_proc_ilocked(ref->proc);
                        } else {
                                if (ref->freeze->sent && ref->freeze->is_frozen != is_frozen)
                                        ref->freeze->resend = true;
                                ref->freeze->is_frozen = is_frozen;
                        }
                        binder_inner_proc_unlock(ref->proc);
                }
                prev = node;
                binder_node_unlock(node);
                binder_inner_proc_lock(proc);
                if (proc->is_dead)
                        break;
        }
        binder_inner_proc_unlock(proc);
        if (prev)
                binder_put_node(prev);
}

static int binder_ioctl_freeze(struct binder_freeze_info *info,
                               struct binder_proc *target_proc)
{
        int ret = 0;

        if (!info->enable) {
                binder_inner_proc_lock(target_proc);
                target_proc->sync_recv = false;
                target_proc->async_recv = false;
                target_proc->is_frozen = false;
                binder_inner_proc_unlock(target_proc);
                binder_add_freeze_work(target_proc, false);
                return 0;
        }

        /*
         * Freezing the target. Prevent new transactions by
         * setting frozen state. If timeout specified, wait
         * for transactions to drain.
         */
        binder_inner_proc_lock(target_proc);
        target_proc->sync_recv = false;
        target_proc->async_recv = false;
        target_proc->is_frozen = true;
        binder_inner_proc_unlock(target_proc);

        if (info->timeout_ms > 0)
                ret = wait_event_interruptible_timeout(
                        target_proc->freeze_wait,
                        (!target_proc->outstanding_txns),
                        msecs_to_jiffies(info->timeout_ms));

        /* Check pending transactions that wait for reply */
        if (ret >= 0) {
                binder_inner_proc_lock(target_proc);
                if (binder_txns_pending_ilocked(target_proc))
                        ret = -EAGAIN;
                binder_inner_proc_unlock(target_proc);
        }

        if (ret < 0) {
                binder_inner_proc_lock(target_proc);
                target_proc->is_frozen = false;
                binder_inner_proc_unlock(target_proc);
        } else {
                binder_add_freeze_work(target_proc, true);
        }

        return ret;
}

static int binder_ioctl_get_freezer_info(
                                struct binder_frozen_status_info *info)
{
        struct binder_proc *target_proc;
        bool found = false;
        __u32 txns_pending;

        info->sync_recv = 0;
        info->async_recv = 0;

        mutex_lock(&binder_procs_lock);
        hlist_for_each_entry(target_proc, &binder_procs, proc_node) {
                if (target_proc->pid == info->pid) {
                        found = true;
                        binder_inner_proc_lock(target_proc);
                        txns_pending = binder_txns_pending_ilocked(target_proc);
                        info->sync_recv |= target_proc->sync_recv |
                                        (txns_pending << 1);
                        info->async_recv |= target_proc->async_recv;
                        binder_inner_proc_unlock(target_proc);
                }
        }
        mutex_unlock(&binder_procs_lock);

        if (!found)
                return -EINVAL;

        return 0;
}

static int binder_ioctl_get_extended_error(struct binder_thread *thread,
                                           void __user *ubuf)
{
        struct binder_extended_error ee;

        binder_inner_proc_lock(thread->proc);
        ee = thread->ee;
        binder_set_extended_error(&thread->ee, 0, BR_OK, 0);
        binder_inner_proc_unlock(thread->proc);

        if (copy_to_user(ubuf, &ee, sizeof(ee)))
                return -EFAULT;

        return 0;
}

static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
        int ret;
        struct binder_proc *proc = filp->private_data;
        struct binder_thread *thread;
        void __user *ubuf = (void __user *)arg;

        /*pr_info("binder_ioctl: %d:%d %x %lx\n",
                        proc->pid, current->pid, cmd, arg);*/

        binder_selftest_alloc(&proc->alloc);

        trace_binder_ioctl(cmd, arg);

        ret = wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
        if (ret)
                goto err_unlocked;

        thread = binder_get_thread(proc);
        if (thread == NULL) {
                ret = -ENOMEM;
                goto err;
        }

        switch (cmd) {
        case BINDER_WRITE_READ:
                ret = binder_ioctl_write_read(filp, arg, thread);
                if (ret)
                        goto err;
                break;
        case BINDER_SET_MAX_THREADS: {
                u32 max_threads;

                if (copy_from_user(&max_threads, ubuf,
                                   sizeof(max_threads))) {
                        ret = -EINVAL;
                        goto err;
                }
                binder_inner_proc_lock(proc);
                proc->max_threads = max_threads;
                binder_inner_proc_unlock(proc);
                break;
        }
        case BINDER_SET_CONTEXT_MGR_EXT: {
                struct flat_binder_object fbo;

                if (copy_from_user(&fbo, ubuf, sizeof(fbo))) {
                        ret = -EINVAL;
                        goto err;
                }
                ret = binder_ioctl_set_ctx_mgr(filp, &fbo);
                if (ret)
                        goto err;
                break;
        }
        case BINDER_SET_CONTEXT_MGR:
                ret = binder_ioctl_set_ctx_mgr(filp, NULL);
                if (ret)
                        goto err;
                break;
        case BINDER_THREAD_EXIT:
                binder_debug(BINDER_DEBUG_THREADS, "%d:%d exit\n",
                             proc->pid, thread->pid);
                binder_thread_release(proc, thread);
                thread = NULL;
                break;
        case BINDER_VERSION: {
                struct binder_version __user *ver = ubuf;

                if (put_user(BINDER_CURRENT_PROTOCOL_VERSION,
                             &ver->protocol_version)) {
                        ret = -EINVAL;
                        goto err;
                }
                break;
        }
        case BINDER_GET_NODE_INFO_FOR_REF: {
                struct binder_node_info_for_ref info;

                if (copy_from_user(&info, ubuf, sizeof(info))) {
                        ret = -EFAULT;
                        goto err;
                }

                ret = binder_ioctl_get_node_info_for_ref(proc, &info);
                if (ret < 0)
                        goto err;

                if (copy_to_user(ubuf, &info, sizeof(info))) {
                        ret = -EFAULT;
                        goto err;
                }

                break;
        }
        case BINDER_GET_NODE_DEBUG_INFO: {
                struct binder_node_debug_info info;

                if (copy_from_user(&info, ubuf, sizeof(info))) {
                        ret = -EFAULT;
                        goto err;
                }

                ret = binder_ioctl_get_node_debug_info(proc, &info);
                if (ret < 0)
                        goto err;

                if (copy_to_user(ubuf, &info, sizeof(info))) {
                        ret = -EFAULT;
                        goto err;
                }
                break;
        }
        case BINDER_FREEZE: {
                struct binder_freeze_info info;
                struct binder_proc **target_procs = NULL, *target_proc;
                int target_procs_count = 0, i = 0;

                ret = 0;

                if (copy_from_user(&info, ubuf, sizeof(info))) {
                        ret = -EFAULT;
                        goto err;
                }

                mutex_lock(&binder_procs_lock);
                hlist_for_each_entry(target_proc, &binder_procs, proc_node) {
                        if (target_proc->pid == info.pid)
                                target_procs_count++;
                }

                if (target_procs_count == 0) {
                        mutex_unlock(&binder_procs_lock);
                        ret = -EINVAL;
                        goto err;
                }

                target_procs = kcalloc(target_procs_count,
                                       sizeof(struct binder_proc *),
                                       GFP_KERNEL);

                if (!target_procs) {
                        mutex_unlock(&binder_procs_lock);
                        ret = -ENOMEM;
                        goto err;
                }

                hlist_for_each_entry(target_proc, &binder_procs, proc_node) {
                        if (target_proc->pid != info.pid)
                                continue;

                        binder_inner_proc_lock(target_proc);
                        target_proc->tmp_ref++;
                        binder_inner_proc_unlock(target_proc);

                        target_procs[i++] = target_proc;
                }
                mutex_unlock(&binder_procs_lock);

                for (i = 0; i < target_procs_count; i++) {
                        if (ret >= 0)
                                ret = binder_ioctl_freeze(&info,
                                                          target_procs[i]);

                        binder_proc_dec_tmpref(target_procs[i]);
                }

                kfree(target_procs);

                if (ret < 0)
                        goto err;
                break;
        }
        case BINDER_GET_FROZEN_INFO: {
                struct binder_frozen_status_info info;

                if (copy_from_user(&info, ubuf, sizeof(info))) {
                        ret = -EFAULT;
                        goto err;
                }

                ret = binder_ioctl_get_freezer_info(&info);
                if (ret < 0)
                        goto err;

                if (copy_to_user(ubuf, &info, sizeof(info))) {
                        ret = -EFAULT;
                        goto err;
                }
                break;
        }
        case BINDER_ENABLE_ONEWAY_SPAM_DETECTION: {
                uint32_t enable;

                if (copy_from_user(&enable, ubuf, sizeof(enable))) {
                        ret = -EFAULT;
                        goto err;
                }
                binder_inner_proc_lock(proc);
                proc->oneway_spam_detection_enabled = (bool)enable;
                binder_inner_proc_unlock(proc);
                break;
        }
        case BINDER_GET_EXTENDED_ERROR:
                ret = binder_ioctl_get_extended_error(thread, ubuf);
                if (ret < 0)
                        goto err;
                break;
        default:
                ret = -EINVAL;
                goto err;
        }
        ret = 0;
err:
        if (thread)
                thread->looper_need_return = false;
        wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
        if (ret && ret != -EINTR)
                pr_info("%d:%d ioctl %x %lx returned %d\n", proc->pid, current->pid, cmd, arg, ret);
err_unlocked:
        trace_binder_ioctl_done(ret);
        return ret;
}

static void binder_vma_open(struct vm_area_struct *vma)
{
        struct binder_proc *proc = vma->vm_private_data;

        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "%d open vm area %lx-%lx (%ld K) vma %lx pagep %lx\n",
                     proc->pid, vma->vm_start, vma->vm_end,
                     (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
                     (unsigned long)pgprot_val(vma->vm_page_prot));
}

static void binder_vma_close(struct vm_area_struct *vma)
{
        struct binder_proc *proc = vma->vm_private_data;

        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "%d close vm area %lx-%lx (%ld K) vma %lx pagep %lx\n",
                     proc->pid, vma->vm_start, vma->vm_end,
                     (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
                     (unsigned long)pgprot_val(vma->vm_page_prot));
        binder_alloc_vma_close(&proc->alloc);
}

static vm_fault_t binder_vm_fault(struct vm_fault *vmf)
{
        return VM_FAULT_SIGBUS;
}

static const struct vm_operations_struct binder_vm_ops = {
        .open = binder_vma_open,
        .close = binder_vma_close,
        .fault = binder_vm_fault,
};

static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
{
        struct binder_proc *proc = filp->private_data;

        if (proc->tsk != current->group_leader)
                return -EINVAL;

        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "%s: %d %lx-%lx (%ld K) vma %lx pagep %lx\n",
                     __func__, proc->pid, vma->vm_start, vma->vm_end,
                     (vma->vm_end - vma->vm_start) / SZ_1K, vma->vm_flags,
                     (unsigned long)pgprot_val(vma->vm_page_prot));

        if (vma->vm_flags & FORBIDDEN_MMAP_FLAGS) {
                pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
                       proc->pid, vma->vm_start, vma->vm_end, "bad vm_flags", -EPERM);
                return -EPERM;
        }
        vm_flags_mod(vma, VM_DONTCOPY | VM_MIXEDMAP, VM_MAYWRITE);

        vma->vm_ops = &binder_vm_ops;
        vma->vm_private_data = proc;

        return binder_alloc_mmap_handler(&proc->alloc, vma);
}

static int binder_open(struct inode *nodp, struct file *filp)
{
        struct binder_proc *proc, *itr;
        struct binder_device *binder_dev;
        struct binderfs_info *info;
        struct dentry *binder_binderfs_dir_entry_proc = NULL;
        bool existing_pid = false;

        binder_debug(BINDER_DEBUG_OPEN_CLOSE, "%s: %d:%d\n", __func__,
                     current->group_leader->pid, current->pid);

        proc = kzalloc(sizeof(*proc), GFP_KERNEL);
        if (proc == NULL)
                return -ENOMEM;

        dbitmap_init(&proc->dmap);
        spin_lock_init(&proc->inner_lock);
        spin_lock_init(&proc->outer_lock);
        get_task_struct(current->group_leader);
        proc->tsk = current->group_leader;
        proc->cred = get_cred(filp->f_cred);
        INIT_LIST_HEAD(&proc->todo);
        init_waitqueue_head(&proc->freeze_wait);
        proc->default_priority = task_nice(current);
        /* binderfs stashes devices in i_private */
        if (is_binderfs_device(nodp)) {
                binder_dev = nodp->i_private;
                info = nodp->i_sb->s_fs_info;
                binder_binderfs_dir_entry_proc = info->proc_log_dir;
        } else {
                binder_dev = container_of(filp->private_data,
                                          struct binder_device, miscdev);
        }
        refcount_inc(&binder_dev->ref);
        proc->context = &binder_dev->context;
        binder_alloc_init(&proc->alloc);

        binder_stats_created(BINDER_STAT_PROC);
        proc->pid = current->group_leader->pid;
        INIT_LIST_HEAD(&proc->delivered_death);
        INIT_LIST_HEAD(&proc->delivered_freeze);
        INIT_LIST_HEAD(&proc->waiting_threads);
        filp->private_data = proc;

        mutex_lock(&binder_procs_lock);
        hlist_for_each_entry(itr, &binder_procs, proc_node) {
                if (itr->pid == proc->pid) {
                        existing_pid = true;
                        break;
                }
        }
        hlist_add_head(&proc->proc_node, &binder_procs);
        mutex_unlock(&binder_procs_lock);

        if (binder_debugfs_dir_entry_proc && !existing_pid) {
                char strbuf[11];

                snprintf(strbuf, sizeof(strbuf), "%u", proc->pid);
                /*
                 * proc debug entries are shared between contexts.
                 * Only create for the first PID to avoid debugfs log spamming
                 * The printing code will anyway print all contexts for a given
                 * PID so this is not a problem.
                 */
                proc->debugfs_entry = debugfs_create_file(strbuf, 0444,
                        binder_debugfs_dir_entry_proc,
                        (void *)(unsigned long)proc->pid,
                        &proc_fops);
        }

        if (binder_binderfs_dir_entry_proc && !existing_pid) {
                char strbuf[11];
                struct dentry *binderfs_entry;

                snprintf(strbuf, sizeof(strbuf), "%u", proc->pid);
                /*
                 * Similar to debugfs, the process specific log file is shared
                 * between contexts. Only create for the first PID.
                 * This is ok since same as debugfs, the log file will contain
                 * information on all contexts of a given PID.
                 */
                binderfs_entry = binderfs_create_file(binder_binderfs_dir_entry_proc,
                        strbuf, &proc_fops, (void *)(unsigned long)proc->pid);
                if (!IS_ERR(binderfs_entry)) {
                        proc->binderfs_entry = binderfs_entry;
                } else {
                        int error;

                        error = PTR_ERR(binderfs_entry);
                        pr_warn("Unable to create file %s in binderfs (error %d)\n",
                                strbuf, error);
                }
        }

        return 0;
}

static int binder_flush(struct file *filp, fl_owner_t id)
{
        struct binder_proc *proc = filp->private_data;

        binder_defer_work(proc, BINDER_DEFERRED_FLUSH);

        return 0;
}

static void binder_deferred_flush(struct binder_proc *proc)
{
        struct rb_node *n;
        int wake_count = 0;

        binder_inner_proc_lock(proc);
        for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n)) {
                struct binder_thread *thread = rb_entry(n, struct binder_thread, rb_node);

                thread->looper_need_return = true;
                if (thread->looper & BINDER_LOOPER_STATE_WAITING) {
                        wake_up_interruptible(&thread->wait);
                        wake_count++;
                }
        }
        binder_inner_proc_unlock(proc);

        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "binder_flush: %d woke %d threads\n", proc->pid,
                     wake_count);
}

static int binder_release(struct inode *nodp, struct file *filp)
{
        struct binder_proc *proc = filp->private_data;

        debugfs_remove(proc->debugfs_entry);

        if (proc->binderfs_entry) {
                binderfs_remove_file(proc->binderfs_entry);
                proc->binderfs_entry = NULL;
        }

        binder_defer_work(proc, BINDER_DEFERRED_RELEASE);

        return 0;
}

static int binder_node_release(struct binder_node *node, int refs)
{
        struct binder_ref *ref;
        int death = 0;
        struct binder_proc *proc = node->proc;

        binder_release_work(proc, &node->async_todo);

        binder_node_lock(node);
        binder_inner_proc_lock(proc);
        binder_dequeue_work_ilocked(&node->work);
        /*
         * The caller must have taken a temporary ref on the node,
         */
        BUG_ON(!node->tmp_refs);
        if (hlist_empty(&node->refs) && node->tmp_refs == 1) {
                binder_inner_proc_unlock(proc);
                binder_node_unlock(node);
                binder_free_node(node);

                return refs;
        }

        node->proc = NULL;
        node->local_strong_refs = 0;
        node->local_weak_refs = 0;
        binder_inner_proc_unlock(proc);

        spin_lock(&binder_dead_nodes_lock);
        hlist_add_head(&node->dead_node, &binder_dead_nodes);
        spin_unlock(&binder_dead_nodes_lock);

        hlist_for_each_entry(ref, &node->refs, node_entry) {
                refs++;
                /*
                 * Need the node lock to synchronize
                 * with new notification requests and the
                 * inner lock to synchronize with queued
                 * death notifications.
                 */
                binder_inner_proc_lock(ref->proc);
                if (!ref->death) {
                        binder_inner_proc_unlock(ref->proc);
                        continue;
                }

                death++;

                BUG_ON(!list_empty(&ref->death->work.entry));
                ref->death->work.type = BINDER_WORK_DEAD_BINDER;
                binder_enqueue_work_ilocked(&ref->death->work,
                                            &ref->proc->todo);
                binder_wakeup_proc_ilocked(ref->proc);
                binder_inner_proc_unlock(ref->proc);
        }

        binder_debug(BINDER_DEBUG_DEAD_BINDER,
                     "node %d now dead, refs %d, death %d\n",
                     node->debug_id, refs, death);
        binder_node_unlock(node);
        binder_put_node(node);

        return refs;
}

static void binder_deferred_release(struct binder_proc *proc)
{
        struct binder_context *context = proc->context;
        struct rb_node *n;
        int threads, nodes, incoming_refs, outgoing_refs, active_transactions;

        mutex_lock(&binder_procs_lock);
        hlist_del(&proc->proc_node);
        mutex_unlock(&binder_procs_lock);

        mutex_lock(&context->context_mgr_node_lock);
        if (context->binder_context_mgr_node &&
            context->binder_context_mgr_node->proc == proc) {
                binder_debug(BINDER_DEBUG_DEAD_BINDER,
                             "%s: %d context_mgr_node gone\n",
                             __func__, proc->pid);
                context->binder_context_mgr_node = NULL;
        }
        mutex_unlock(&context->context_mgr_node_lock);
        binder_inner_proc_lock(proc);
        /*
         * Make sure proc stays alive after we
         * remove all the threads
         */
        proc->tmp_ref++;

        proc->is_dead = true;
        proc->is_frozen = false;
        proc->sync_recv = false;
        proc->async_recv = false;
        threads = 0;
        active_transactions = 0;
        while ((n = rb_first(&proc->threads))) {
                struct binder_thread *thread;

                thread = rb_entry(n, struct binder_thread, rb_node);
                binder_inner_proc_unlock(proc);
                threads++;
                active_transactions += binder_thread_release(proc, thread);
                binder_inner_proc_lock(proc);
        }

        nodes = 0;
        incoming_refs = 0;
        while ((n = rb_first(&proc->nodes))) {
                struct binder_node *node;

                node = rb_entry(n, struct binder_node, rb_node);
                nodes++;
                /*
                 * take a temporary ref on the node before
                 * calling binder_node_release() which will either
                 * kfree() the node or call binder_put_node()
                 */
                binder_inc_node_tmpref_ilocked(node);
                rb_erase(&node->rb_node, &proc->nodes);
                binder_inner_proc_unlock(proc);
                incoming_refs = binder_node_release(node, incoming_refs);
                binder_inner_proc_lock(proc);
        }
        binder_inner_proc_unlock(proc);

        outgoing_refs = 0;
        binder_proc_lock(proc);
        while ((n = rb_first(&proc->refs_by_desc))) {
                struct binder_ref *ref;

                ref = rb_entry(n, struct binder_ref, rb_node_desc);
                outgoing_refs++;
                binder_cleanup_ref_olocked(ref);
                binder_proc_unlock(proc);
                binder_free_ref(ref);
                binder_proc_lock(proc);
        }
        binder_proc_unlock(proc);

        binder_release_work(proc, &proc->todo);
        binder_release_work(proc, &proc->delivered_death);
        binder_release_work(proc, &proc->delivered_freeze);

        binder_debug(BINDER_DEBUG_OPEN_CLOSE,
                     "%s: %d threads %d, nodes %d (ref %d), refs %d, active transactions %d\n",
                     __func__, proc->pid, threads, nodes, incoming_refs,
                     outgoing_refs, active_transactions);

        binder_proc_dec_tmpref(proc);
}

static void binder_deferred_func(struct work_struct *work)
{
        struct binder_proc *proc;

        int defer;

        do {
                mutex_lock(&binder_deferred_lock);
                if (!hlist_empty(&binder_deferred_list)) {
                        proc = hlist_entry(binder_deferred_list.first,
                                        struct binder_proc, deferred_work_node);
                        hlist_del_init(&proc->deferred_work_node);
                        defer = proc->deferred_work;
                        proc->deferred_work = 0;
                } else {
                        proc = NULL;
                        defer = 0;
                }
                mutex_unlock(&binder_deferred_lock);

                if (defer & BINDER_DEFERRED_FLUSH)
                        binder_deferred_flush(proc);

                if (defer & BINDER_DEFERRED_RELEASE)
                        binder_deferred_release(proc); /* frees proc */
        } while (proc);
}
static DECLARE_WORK(binder_deferred_work, binder_deferred_func);

static void
binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer)
{
        mutex_lock(&binder_deferred_lock);
        proc->deferred_work |= defer;
        if (hlist_unhashed(&proc->deferred_work_node)) {
                hlist_add_head(&proc->deferred_work_node,
                                &binder_deferred_list);
                schedule_work(&binder_deferred_work);
        }
        mutex_unlock(&binder_deferred_lock);
}

static void print_binder_transaction_ilocked(struct seq_file *m,
                                             struct binder_proc *proc,
                                             const char *prefix,
                                             struct binder_transaction *t)
{
        struct binder_proc *to_proc;
        struct binder_buffer *buffer = t->buffer;
        ktime_t current_time = ktime_get();

        spin_lock(&t->lock);
        to_proc = t->to_proc;
        seq_printf(m,
                   "%s %d: %pK from %d:%d to %d:%d code %x flags %x pri %ld r%d elapsed %lldms",
                   prefix, t->debug_id, t,
                   t->from_pid,
                   t->from_tid,
                   to_proc ? to_proc->pid : 0,
                   t->to_thread ? t->to_thread->pid : 0,
                   t->code, t->flags, t->priority, t->need_reply,
                   ktime_ms_delta(current_time, t->start_time));
        spin_unlock(&t->lock);

        if (proc != to_proc) {
                /*
                 * Can only safely deref buffer if we are holding the
                 * correct proc inner lock for this node
                 */
                seq_puts(m, "\n");
                return;
        }

        if (buffer == NULL) {
                seq_puts(m, " buffer free\n");
                return;
        }
        if (buffer->target_node)
                seq_printf(m, " node %d", buffer->target_node->debug_id);
        seq_printf(m, " size %zd:%zd offset %lx\n",
                   buffer->data_size, buffer->offsets_size,
                   proc->alloc.buffer - buffer->user_data);
}

static void print_binder_work_ilocked(struct seq_file *m,
                                     struct binder_proc *proc,
                                     const char *prefix,
                                     const char *transaction_prefix,
                                     struct binder_work *w)
{
        struct binder_node *node;
        struct binder_transaction *t;

        switch (w->type) {
        case BINDER_WORK_TRANSACTION:
                t = container_of(w, struct binder_transaction, work);
                print_binder_transaction_ilocked(
                                m, proc, transaction_prefix, t);
                break;
        case BINDER_WORK_RETURN_ERROR: {
                struct binder_error *e = container_of(
                                w, struct binder_error, work);

                seq_printf(m, "%stransaction error: %u\n",
                           prefix, e->cmd);
        } break;
        case BINDER_WORK_TRANSACTION_COMPLETE:
                seq_printf(m, "%stransaction complete\n", prefix);
                break;
        case BINDER_WORK_NODE:
                node = container_of(w, struct binder_node, work);
                seq_printf(m, "%snode work %d: u%016llx c%016llx\n",
                           prefix, node->debug_id,
                           (u64)node->ptr, (u64)node->cookie);
                break;
        case BINDER_WORK_DEAD_BINDER:
                seq_printf(m, "%shas dead binder\n", prefix);
                break;
        case BINDER_WORK_DEAD_BINDER_AND_CLEAR:
                seq_printf(m, "%shas cleared dead binder\n", prefix);
                break;
        case BINDER_WORK_CLEAR_DEATH_NOTIFICATION:
                seq_printf(m, "%shas cleared death notification\n", prefix);
                break;
        case BINDER_WORK_FROZEN_BINDER:
                seq_printf(m, "%shas frozen binder\n", prefix);
                break;
        case BINDER_WORK_CLEAR_FREEZE_NOTIFICATION:
                seq_printf(m, "%shas cleared freeze notification\n", prefix);
                break;
        default:
                seq_printf(m, "%sunknown work: type %d\n", prefix, w->type);
                break;
        }
}

static void print_binder_thread_ilocked(struct seq_file *m,
                                        struct binder_thread *thread,
                                        int print_always)
{
        struct binder_transaction *t;
        struct binder_work *w;
        size_t start_pos = m->count;
        size_t header_pos;

        seq_printf(m, "  thread %d: l %02x need_return %d tr %d\n",
                        thread->pid, thread->looper,
                        thread->looper_need_return,
                        atomic_read(&thread->tmp_ref));
        header_pos = m->count;
        t = thread->transaction_stack;
        while (t) {
                if (t->from == thread) {
                        print_binder_transaction_ilocked(m, thread->proc,
                                        "    outgoing transaction", t);
                        t = t->from_parent;
                } else if (t->to_thread == thread) {
                        print_binder_transaction_ilocked(m, thread->proc,
                                                 "    incoming transaction", t);
                        t = t->to_parent;
                } else {
                        print_binder_transaction_ilocked(m, thread->proc,
                                        "    bad transaction", t);
                        t = NULL;
                }
        }
        list_for_each_entry(w, &thread->todo, entry) {
                print_binder_work_ilocked(m, thread->proc, "    ",
                                          "    pending transaction", w);
        }
        if (!print_always && m->count == header_pos)
                m->count = start_pos;
}

static void print_binder_node_nilocked(struct seq_file *m,
                                       struct binder_node *node)
{
        struct binder_ref *ref;
        struct binder_work *w;
        int count;

        count = hlist_count_nodes(&node->refs);

        seq_printf(m, "  node %d: u%016llx c%016llx hs %d hw %d ls %d lw %d is %d iw %d tr %d",
                   node->debug_id, (u64)node->ptr, (u64)node->cookie,
                   node->has_strong_ref, node->has_weak_ref,
                   node->local_strong_refs, node->local_weak_refs,
                   node->internal_strong_refs, count, node->tmp_refs);
        if (count) {
                seq_puts(m, " proc");
                hlist_for_each_entry(ref, &node->refs, node_entry)
                        seq_printf(m, " %d", ref->proc->pid);
        }
        seq_puts(m, "\n");
        if (node->proc) {
                list_for_each_entry(w, &node->async_todo, entry)
                        print_binder_work_ilocked(m, node->proc, "    ",
                                          "    pending async transaction", w);
        }
}

static void print_binder_ref_olocked(struct seq_file *m,
                                     struct binder_ref *ref)
{
        binder_node_lock(ref->node);
        seq_printf(m, "  ref %d: desc %d %snode %d s %d w %d d %pK\n",
                   ref->data.debug_id, ref->data.desc,
                   ref->node->proc ? "" : "dead ",
                   ref->node->debug_id, ref->data.strong,
                   ref->data.weak, ref->death);
        binder_node_unlock(ref->node);
}

static void print_binder_proc(struct seq_file *m,
                              struct binder_proc *proc, int print_all)
{
        struct binder_work *w;
        struct rb_node *n;
        size_t start_pos = m->count;
        size_t header_pos;
        struct binder_node *last_node = NULL;

        seq_printf(m, "proc %d\n", proc->pid);
        seq_printf(m, "context %s\n", proc->context->name);
        header_pos = m->count;

        binder_inner_proc_lock(proc);
        for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n))
                print_binder_thread_ilocked(m, rb_entry(n, struct binder_thread,
                                                rb_node), print_all);

        for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n)) {
                struct binder_node *node = rb_entry(n, struct binder_node,
                                                    rb_node);
                if (!print_all && !node->has_async_transaction)
                        continue;

                /*
                 * take a temporary reference on the node so it
                 * survives and isn't removed from the tree
                 * while we print it.
                 */
                binder_inc_node_tmpref_ilocked(node);
                /* Need to drop inner lock to take node lock */
                binder_inner_proc_unlock(proc);
                if (last_node)
                        binder_put_node(last_node);
                binder_node_inner_lock(node);
                print_binder_node_nilocked(m, node);
                binder_node_inner_unlock(node);
                last_node = node;
                binder_inner_proc_lock(proc);
        }
        binder_inner_proc_unlock(proc);
        if (last_node)
                binder_put_node(last_node);

        if (print_all) {
                binder_proc_lock(proc);
                for (n = rb_first(&proc->refs_by_desc);
                     n != NULL;
                     n = rb_next(n))
                        print_binder_ref_olocked(m, rb_entry(n,
                                                            struct binder_ref,
                                                            rb_node_desc));
                binder_proc_unlock(proc);
        }
        binder_alloc_print_allocated(m, &proc->alloc);
        binder_inner_proc_lock(proc);
        list_for_each_entry(w, &proc->todo, entry)
                print_binder_work_ilocked(m, proc, "  ",
                                          "  pending transaction", w);
        list_for_each_entry(w, &proc->delivered_death, entry) {
                seq_puts(m, "  has delivered dead binder\n");
                break;
        }
        list_for_each_entry(w, &proc->delivered_freeze, entry) {
                seq_puts(m, "  has delivered freeze binder\n");
                break;
        }
        binder_inner_proc_unlock(proc);
        if (!print_all && m->count == header_pos)
                m->count = start_pos;
}

static const char * const binder_return_strings[] = {
        "BR_ERROR",
        "BR_OK",
        "BR_TRANSACTION",
        "BR_REPLY",
        "BR_ACQUIRE_RESULT",
        "BR_DEAD_REPLY",
        "BR_TRANSACTION_COMPLETE",
        "BR_INCREFS",
        "BR_ACQUIRE",
        "BR_RELEASE",
        "BR_DECREFS",
        "BR_ATTEMPT_ACQUIRE",
        "BR_NOOP",
        "BR_SPAWN_LOOPER",
        "BR_FINISHED",
        "BR_DEAD_BINDER",
        "BR_CLEAR_DEATH_NOTIFICATION_DONE",
        "BR_FAILED_REPLY",
        "BR_FROZEN_REPLY",
        "BR_ONEWAY_SPAM_SUSPECT",
        "BR_TRANSACTION_PENDING_FROZEN",
        "BR_FROZEN_BINDER",
        "BR_CLEAR_FREEZE_NOTIFICATION_DONE",
};

static const char * const binder_command_strings[] = {
        "BC_TRANSACTION",
        "BC_REPLY",
        "BC_ACQUIRE_RESULT",
        "BC_FREE_BUFFER",
        "BC_INCREFS",
        "BC_ACQUIRE",
        "BC_RELEASE",
        "BC_DECREFS",
        "BC_INCREFS_DONE",
        "BC_ACQUIRE_DONE",
        "BC_ATTEMPT_ACQUIRE",
        "BC_REGISTER_LOOPER",
        "BC_ENTER_LOOPER",
        "BC_EXIT_LOOPER",
        "BC_REQUEST_DEATH_NOTIFICATION",
        "BC_CLEAR_DEATH_NOTIFICATION",
        "BC_DEAD_BINDER_DONE",
        "BC_TRANSACTION_SG",
        "BC_REPLY_SG",
        "BC_REQUEST_FREEZE_NOTIFICATION",
        "BC_CLEAR_FREEZE_NOTIFICATION",
        "BC_FREEZE_NOTIFICATION_DONE",
};

static const char * const binder_objstat_strings[] = {
        "proc",
        "thread",
        "node",
        "ref",
        "death",
        "transaction",
        "transaction_complete",
        "freeze",
};

static void print_binder_stats(struct seq_file *m, const char *prefix,
                               struct binder_stats *stats)
{
        int i;

        BUILD_BUG_ON(ARRAY_SIZE(stats->bc) !=
                     ARRAY_SIZE(binder_command_strings));
        for (i = 0; i < ARRAY_SIZE(stats->bc); i++) {
                int temp = atomic_read(&stats->bc[i]);

                if (temp)
                        seq_printf(m, "%s%s: %d\n", prefix,
                                   binder_command_strings[i], temp);
        }

        BUILD_BUG_ON(ARRAY_SIZE(stats->br) !=
                     ARRAY_SIZE(binder_return_strings));
        for (i = 0; i < ARRAY_SIZE(stats->br); i++) {
                int temp = atomic_read(&stats->br[i]);

                if (temp)
                        seq_printf(m, "%s%s: %d\n", prefix,
                                   binder_return_strings[i], temp);
        }

        BUILD_BUG_ON(ARRAY_SIZE(stats->obj_created) !=
                     ARRAY_SIZE(binder_objstat_strings));
        BUILD_BUG_ON(ARRAY_SIZE(stats->obj_created) !=
                     ARRAY_SIZE(stats->obj_deleted));
        for (i = 0; i < ARRAY_SIZE(stats->obj_created); i++) {
                int created = atomic_read(&stats->obj_created[i]);
                int deleted = atomic_read(&stats->obj_deleted[i]);

                if (created || deleted)
                        seq_printf(m, "%s%s: active %d total %d\n",
                                prefix,
                                binder_objstat_strings[i],
                                created - deleted,
                                created);
        }
}

static void print_binder_proc_stats(struct seq_file *m,
                                    struct binder_proc *proc)
{
        struct binder_work *w;
        struct binder_thread *thread;
        struct rb_node *n;
        int count, strong, weak, ready_threads;
        size_t free_async_space =
                binder_alloc_get_free_async_space(&proc->alloc);

        seq_printf(m, "proc %d\n", proc->pid);
        seq_printf(m, "context %s\n", proc->context->name);
        count = 0;
        ready_threads = 0;
        binder_inner_proc_lock(proc);
        for (n = rb_first(&proc->threads); n != NULL; n = rb_next(n))
                count++;

        list_for_each_entry(thread, &proc->waiting_threads, waiting_thread_node)
                ready_threads++;

        seq_printf(m, "  threads: %d\n", count);
        seq_printf(m, "  requested threads: %d+%d/%d\n"
                        "  ready threads %d\n"
                        "  free async space %zd\n", proc->requested_threads,
                        proc->requested_threads_started, proc->max_threads,
                        ready_threads,
                        free_async_space);
        count = 0;
        for (n = rb_first(&proc->nodes); n != NULL; n = rb_next(n))
                count++;
        binder_inner_proc_unlock(proc);
        seq_printf(m, "  nodes: %d\n", count);
        count = 0;
        strong = 0;
        weak = 0;
        binder_proc_lock(proc);
        for (n = rb_first(&proc->refs_by_desc); n != NULL; n = rb_next(n)) {
                struct binder_ref *ref = rb_entry(n, struct binder_ref,
                                                  rb_node_desc);
                count++;
                strong += ref->data.strong;
                weak += ref->data.weak;
        }
        binder_proc_unlock(proc);
        seq_printf(m, "  refs: %d s %d w %d\n", count, strong, weak);

        count = binder_alloc_get_allocated_count(&proc->alloc);
        seq_printf(m, "  buffers: %d\n", count);

        binder_alloc_print_pages(m, &proc->alloc);

        count = 0;
        binder_inner_proc_lock(proc);
        list_for_each_entry(w, &proc->todo, entry) {
                if (w->type == BINDER_WORK_TRANSACTION)
                        count++;
        }
        binder_inner_proc_unlock(proc);
        seq_printf(m, "  pending transactions: %d\n", count);

        print_binder_stats(m, "  ", &proc->stats);
}

static int state_show(struct seq_file *m, void *unused)
{
        struct binder_proc *proc;
        struct binder_node *node;
        struct binder_node *last_node = NULL;

        seq_puts(m, "binder state:\n");

        spin_lock(&binder_dead_nodes_lock);
        if (!hlist_empty(&binder_dead_nodes))
                seq_puts(m, "dead nodes:\n");
        hlist_for_each_entry(node, &binder_dead_nodes, dead_node) {
                /*
                 * take a temporary reference on the node so it
                 * survives and isn't removed from the list
                 * while we print it.
                 */
                node->tmp_refs++;
                spin_unlock(&binder_dead_nodes_lock);
                if (last_node)
                        binder_put_node(last_node);
                binder_node_lock(node);
                print_binder_node_nilocked(m, node);
                binder_node_unlock(node);
                last_node = node;
                spin_lock(&binder_dead_nodes_lock);
        }
        spin_unlock(&binder_dead_nodes_lock);
        if (last_node)
                binder_put_node(last_node);

        mutex_lock(&binder_procs_lock);
        hlist_for_each_entry(proc, &binder_procs, proc_node)
                print_binder_proc(m, proc, 1);
        mutex_unlock(&binder_procs_lock);

        return 0;
}

static int stats_show(struct seq_file *m, void *unused)
{
        struct binder_proc *proc;

        seq_puts(m, "binder stats:\n");

        print_binder_stats(m, "", &binder_stats);

        mutex_lock(&binder_procs_lock);
        hlist_for_each_entry(proc, &binder_procs, proc_node)
                print_binder_proc_stats(m, proc);
        mutex_unlock(&binder_procs_lock);

        return 0;
}

static int transactions_show(struct seq_file *m, void *unused)
{
        struct binder_proc *proc;

        seq_puts(m, "binder transactions:\n");
        mutex_lock(&binder_procs_lock);
        hlist_for_each_entry(proc, &binder_procs, proc_node)
                print_binder_proc(m, proc, 0);
        mutex_unlock(&binder_procs_lock);

        return 0;
}

static int proc_show(struct seq_file *m, void *unused)
{
        struct binder_proc *itr;
        int pid = (unsigned long)m->private;

        mutex_lock(&binder_procs_lock);
        hlist_for_each_entry(itr, &binder_procs, proc_node) {
                if (itr->pid == pid) {
                        seq_puts(m, "binder proc state:\n");
                        print_binder_proc(m, itr, 1);
                }
        }
        mutex_unlock(&binder_procs_lock);

        return 0;
}

static void print_binder_transaction_log_entry(struct seq_file *m,
                                        struct binder_transaction_log_entry *e)
{
        int debug_id = READ_ONCE(e->debug_id_done);
        /*
         * read barrier to guarantee debug_id_done read before
         * we print the log values
         */
        smp_rmb();
        seq_printf(m,
                   "%d: %s from %d:%d to %d:%d context %s node %d handle %d size %d:%d ret %d/%d l=%d",
                   e->debug_id, (e->call_type == 2) ? "reply" :
                   ((e->call_type == 1) ? "async" : "call "), e->from_proc,
                   e->from_thread, e->to_proc, e->to_thread, e->context_name,
                   e->to_node, e->target_handle, e->data_size, e->offsets_size,
                   e->return_error, e->return_error_param,
                   e->return_error_line);
        /*
         * read-barrier to guarantee read of debug_id_done after
         * done printing the fields of the entry
         */
        smp_rmb();
        seq_printf(m, debug_id && debug_id == READ_ONCE(e->debug_id_done) ?
                        "\n" : " (incomplete)\n");
}

static int transaction_log_show(struct seq_file *m, void *unused)
{
        struct binder_transaction_log *log = m->private;
        unsigned int log_cur = atomic_read(&log->cur);
        unsigned int count;
        unsigned int cur;
        int i;

        count = log_cur + 1;
        cur = count < ARRAY_SIZE(log->entry) && !log->full ?
                0 : count % ARRAY_SIZE(log->entry);
        if (count > ARRAY_SIZE(log->entry) || log->full)
                count = ARRAY_SIZE(log->entry);
        for (i = 0; i < count; i++) {
                unsigned int index = cur++ % ARRAY_SIZE(log->entry);

                print_binder_transaction_log_entry(m, &log->entry[index]);
        }
        return 0;
}

const struct file_operations binder_fops = {
        .owner = THIS_MODULE,
        .poll = binder_poll,
        .unlocked_ioctl = binder_ioctl,
        .compat_ioctl = compat_ptr_ioctl,
        .mmap = binder_mmap,
        .open = binder_open,
        .flush = binder_flush,
        .release = binder_release,
};

DEFINE_SHOW_ATTRIBUTE(state);
DEFINE_SHOW_ATTRIBUTE(stats);
DEFINE_SHOW_ATTRIBUTE(transactions);
DEFINE_SHOW_ATTRIBUTE(transaction_log);

const struct binder_debugfs_entry binder_debugfs_entries[] = {
        {
                .name = "state",
                .mode = 0444,
                .fops = &state_fops,
                .data = NULL,
        },
        {
                .name = "stats",
                .mode = 0444,
                .fops = &stats_fops,
                .data = NULL,
        },
        {
                .name = "transactions",
                .mode = 0444,
                .fops = &transactions_fops,
                .data = NULL,
        },
        {
                .name = "transaction_log",
                .mode = 0444,
                .fops = &transaction_log_fops,
                .data = &binder_transaction_log,
        },
        {
                .name = "failed_transaction_log",
                .mode = 0444,
                .fops = &transaction_log_fops,
                .data = &binder_transaction_log_failed,
        },
        {} /* terminator */
};

static int __init init_binder_device(const char *name)
{
        int ret;
        struct binder_device *binder_device;

        binder_device = kzalloc(sizeof(*binder_device), GFP_KERNEL);
        if (!binder_device)
                return -ENOMEM;

        binder_device->miscdev.fops = &binder_fops;
        binder_device->miscdev.minor = MISC_DYNAMIC_MINOR;
        binder_device->miscdev.name = name;

        refcount_set(&binder_device->ref, 1);
        binder_device->context.binder_context_mgr_uid = INVALID_UID;
        binder_device->context.name = name;
        mutex_init(&binder_device->context.context_mgr_node_lock);

        ret = misc_register(&binder_device->miscdev);
        if (ret < 0) {
                kfree(binder_device);
                return ret;
        }

        hlist_add_head(&binder_device->hlist, &binder_devices);

        return ret;
}

static int __init binder_init(void)
{
        int ret;
        char *device_name, *device_tmp;
        struct binder_device *device;
        struct hlist_node *tmp;
        char *device_names = NULL;
        const struct binder_debugfs_entry *db_entry;

        ret = binder_alloc_shrinker_init();
        if (ret)
                return ret;

        atomic_set(&binder_transaction_log.cur, ~0U);
        atomic_set(&binder_transaction_log_failed.cur, ~0U);

        binder_debugfs_dir_entry_root = debugfs_create_dir("binder", NULL);

        binder_for_each_debugfs_entry(db_entry)
                debugfs_create_file(db_entry->name,
                                        db_entry->mode,
                                        binder_debugfs_dir_entry_root,
                                        db_entry->data,
                                        db_entry->fops);

        binder_debugfs_dir_entry_proc = debugfs_create_dir("proc",
                                                binder_debugfs_dir_entry_root);

        if (!IS_ENABLED(CONFIG_ANDROID_BINDERFS) &&
            strcmp(binder_devices_param, "") != 0) {
                /*
                * Copy the module_parameter string, because we don't want to
                * tokenize it in-place.
                 */
                device_names = kstrdup(binder_devices_param, GFP_KERNEL);
                if (!device_names) {
                        ret = -ENOMEM;
                        goto err_alloc_device_names_failed;
                }

                device_tmp = device_names;
                while ((device_name = strsep(&device_tmp, ","))) {
                        ret = init_binder_device(device_name);
                        if (ret)
                                goto err_init_binder_device_failed;
                }
        }

        ret = init_binderfs();
        if (ret)
                goto err_init_binder_device_failed;

        return ret;

err_init_binder_device_failed:
        hlist_for_each_entry_safe(device, tmp, &binder_devices, hlist) {
                misc_deregister(&device->miscdev);
                hlist_del(&device->hlist);
                kfree(device);
        }

        kfree(device_names);

err_alloc_device_names_failed:
        debugfs_remove_recursive(binder_debugfs_dir_entry_root);
        binder_alloc_shrinker_exit();

        return ret;
}

device_initcall(binder_init);

#define CREATE_TRACE_POINTS
#include "binder_trace.h"

MODULE_LICENSE("GPL v2");