[linux.git] / lib / spinlock_debug.c

/*
 * Copyright 2005, Red Hat, Inc., Ingo Molnar
 * Released under the General Public License (GPL).
 *
 * This file contains the spinlock/rwlock implementations for
 * DEBUG_SPINLOCK.
 */

#include <linux/spinlock.h>
#include <linux/nmi.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include <linux/delay.h>
#include <linux/module.h>

void __spin_lock_init(spinlock_t *lock, const char *name,
		      struct lock_class_key *key)
{
#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/*
	 * Make sure we are not reinitializing a held lock:
	 */
	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
	lockdep_init_map(&lock->dep_map, name, key, 0);
#endif
	lock->raw_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
	lock->magic = SPINLOCK_MAGIC;
	lock->owner = SPINLOCK_OWNER_INIT;
	lock->owner_cpu = -1;
}

EXPORT_SYMBOL(__spin_lock_init);

void __rwlock_init(rwlock_t *lock, const char *name,
		   struct lock_class_key *key)
{
#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/*
	 * Make sure we are not reinitializing a held lock:
	 */
	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
	lockdep_init_map(&lock->dep_map, name, key, 0);
#endif
	lock->raw_lock = (raw_rwlock_t) __RAW_RW_LOCK_UNLOCKED;
	lock->magic = RWLOCK_MAGIC;
	lock->owner = SPINLOCK_OWNER_INIT;
	lock->owner_cpu = -1;
}

EXPORT_SYMBOL(__rwlock_init);

static void spin_bug(spinlock_t *lock, const char *msg)
{
	struct task_struct *owner = NULL;

	if (!debug_locks_off())
		return;

	if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
		owner = lock->owner;
	printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
		msg, raw_smp_processor_id(),
		current->comm, task_pid_nr(current));
	printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
			".owner_cpu: %d\n",
		lock, lock->magic,
		owner ? owner->comm : "<none>",
		owner ? task_pid_nr(owner) : -1,
		lock->owner_cpu);
	dump_stack();
}

#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)

static inline void
debug_spin_lock_before(spinlock_t *lock)
{
	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
	SPIN_BUG_ON(lock->owner == current, lock, "recursion");
	SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
							lock, "cpu recursion");
}

static inline void debug_spin_lock_after(spinlock_t *lock)
{
	lock->owner_cpu = raw_smp_processor_id();
	lock->owner = current;
}

static inline void debug_spin_unlock(spinlock_t *lock)
{
	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
	SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked");
	SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
	SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
							lock, "wrong CPU");
	lock->owner = SPINLOCK_OWNER_INIT;
	lock->owner_cpu = -1;
}

static void __spin_lock_debug(spinlock_t *lock)
{
	u64 i;
	u64 loops = loops_per_jiffy * HZ;
	int print_once = 1;

	for (;;) {
		for (i = 0; i < loops; i++) {
			if (__raw_spin_trylock(&lock->raw_lock))
				return;
			__delay(1);
		}
		/* lockup suspected: */
		if (print_once) {
			print_once = 0;
			printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "
					"%s/%d, %p\n",
				raw_smp_processor_id(), current->comm,
				task_pid_nr(current), lock);
			dump_stack();
#ifdef CONFIG_SMP
			trigger_all_cpu_backtrace();
#endif
		}
	}
}

void _raw_spin_lock(spinlock_t *lock)
{
	debug_spin_lock_before(lock);
	if (unlikely(!__raw_spin_trylock(&lock->raw_lock)))
		__spin_lock_debug(lock);
	debug_spin_lock_after(lock);
}

int _raw_spin_trylock(spinlock_t *lock)
{
	int ret = __raw_spin_trylock(&lock->raw_lock);

	if (ret)
		debug_spin_lock_after(lock);
#ifndef CONFIG_SMP
	/*
	 * Must not happen on UP:
	 */
	SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
#endif
	return ret;
}

void _raw_spin_unlock(spinlock_t *lock)
{
	debug_spin_unlock(lock);
	__raw_spin_unlock(&lock->raw_lock);
}

static void rwlock_bug(rwlock_t *lock, const char *msg)
{
	if (!debug_locks_off())
		return;

	printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
		msg, raw_smp_processor_id(), current->comm,
		task_pid_nr(current), lock);
	dump_stack();
}

#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)

#if 0		/* __write_lock_debug() can lock up - maybe this can too? */
static void __read_lock_debug(rwlock_t *lock)
{
	u64 i;
	u64 loops = loops_per_jiffy * HZ;
	int print_once = 1;

	for (;;) {
		for (i = 0; i < loops; i++) {
			if (__raw_read_trylock(&lock->raw_lock))
				return;
			__delay(1);
		}
		/* lockup suspected: */
		if (print_once) {
			print_once = 0;
			printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
					"%s/%d, %p\n",
				raw_smp_processor_id(), current->comm,
				current->pid, lock);
			dump_stack();
		}
	}
}
#endif

void _raw_read_lock(rwlock_t *lock)
{
	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
	__raw_read_lock(&lock->raw_lock);
}

int _raw_read_trylock(rwlock_t *lock)
{
	int ret = __raw_read_trylock(&lock->raw_lock);

#ifndef CONFIG_SMP
	/*
	 * Must not happen on UP:
	 */
	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
#endif
	return ret;
}

void _raw_read_unlock(rwlock_t *lock)
{
	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
	__raw_read_unlock(&lock->raw_lock);
}

static inline void debug_write_lock_before(rwlock_t *lock)
{
	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
	RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
	RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
							lock, "cpu recursion");
}

static inline void debug_write_lock_after(rwlock_t *lock)
{
	lock->owner_cpu = raw_smp_processor_id();
	lock->owner = current;
}

static inline void debug_write_unlock(rwlock_t *lock)
{
	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
	RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
	RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
							lock, "wrong CPU");
	lock->owner = SPINLOCK_OWNER_INIT;
	lock->owner_cpu = -1;
}

#if 0		/* This can cause lockups */
static void __write_lock_debug(rwlock_t *lock)
{
	u64 i;
	u64 loops = loops_per_jiffy * HZ;
	int print_once = 1;

	for (;;) {
		for (i = 0; i < loops; i++) {
			if (__raw_write_trylock(&lock->raw_lock))
				return;
			__delay(1);
		}
		/* lockup suspected: */
		if (print_once) {
			print_once = 0;
			printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
					"%s/%d, %p\n",
				raw_smp_processor_id(), current->comm,
				current->pid, lock);
			dump_stack();
		}
	}
}
#endif

void _raw_write_lock(rwlock_t *lock)
{
	debug_write_lock_before(lock);
	__raw_write_lock(&lock->raw_lock);
	debug_write_lock_after(lock);
}

int _raw_write_trylock(rwlock_t *lock)
{
	int ret = __raw_write_trylock(&lock->raw_lock);

	if (ret)
		debug_write_lock_after(lock);
#ifndef CONFIG_SMP
	/*
	 * Must not happen on UP:
	 */
	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
#endif
	return ret;
}

void _raw_write_unlock(rwlock_t *lock)
{
	debug_write_unlock(lock);
	__raw_write_unlock(&lock->raw_lock);
}
Commit	Line	Data
fb1c8f93 IM	1	/*
	2	* Copyright 2005, Red Hat, Inc., Ingo Molnar
	3	* Released under the General Public License (GPL).
	4	*
	5	* This file contains the spinlock/rwlock implementations for
	6	* DEBUG_SPINLOCK.
	7	*/
	8
fb1c8f93	9	#include <linux/spinlock.h>
bb81a09e	10	#include <linux/nmi.h>
fb1c8f93	11	#include <linux/interrupt.h>
9a11b49a	12	#include <linux/debug_locks.h>
fb1c8f93	13	#include <linux/delay.h>
9a11b49a	14	#include <linux/module.h>
fb1c8f93	15
8a25d5de IM	16	void __spin_lock_init(spinlock_t lock, const char name,
	17	struct lock_class_key *key)
	18	{
	19	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	20	/*
	21	* Make sure we are not reinitializing a held lock:
	22	*/
	23	debug_check_no_locks_freed((void )lock, sizeof(lock));
4dfbb9d8	24	lockdep_init_map(&lock->dep_map, name, key, 0);
8a25d5de IM	25	#endif
	26	lock->raw_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
	27	lock->magic = SPINLOCK_MAGIC;
	28	lock->owner = SPINLOCK_OWNER_INIT;
	29	lock->owner_cpu = -1;
	30	}
	31
	32	EXPORT_SYMBOL(__spin_lock_init);
	33
	34	void __rwlock_init(rwlock_t lock, const char name,
	35	struct lock_class_key *key)
	36	{
	37	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	38	/*
	39	* Make sure we are not reinitializing a held lock:
	40	*/
	41	debug_check_no_locks_freed((void )lock, sizeof(lock));
4dfbb9d8	42	lockdep_init_map(&lock->dep_map, name, key, 0);
8a25d5de IM	43	#endif
	44	lock->raw_lock = (raw_rwlock_t) __RAW_RW_LOCK_UNLOCKED;
	45	lock->magic = RWLOCK_MAGIC;
	46	lock->owner = SPINLOCK_OWNER_INIT;
	47	lock->owner_cpu = -1;
	48	}
	49
	50	EXPORT_SYMBOL(__rwlock_init);
	51
fb1c8f93 IM	52	static void spin_bug(spinlock_t lock, const char msg)
fb1c8f93 IM	53	{
fb1c8f93 IM	54	struct task_struct *owner = NULL;
fb1c8f93 IM	55
9a11b49a IM	56	if (!debug_locks_off())
	57	return;
	58
	59	if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
	60	owner = lock->owner;
	61	printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
	62	msg, raw_smp_processor_id(),
ba25f9dc	63	current->comm, task_pid_nr(current));
9a11b49a IM	64	printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
	65	".owner_cpu: %d\n",
	66	lock, lock->magic,
	67	owner ? owner->comm : "<none>",
ba25f9dc	68	owner ? task_pid_nr(owner) : -1,
9a11b49a IM	69	lock->owner_cpu);
9a11b49a IM	70	dump_stack();
fb1c8f93 IM	71	}
	72
	73	#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
	74
9a11b49a IM	75	static inline void
9a11b49a IM	76	debug_spin_lock_before(spinlock_t *lock)
fb1c8f93 IM	77	{
	78	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
	79	SPIN_BUG_ON(lock->owner == current, lock, "recursion");
	80	SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
	81	lock, "cpu recursion");
	82	}
	83
	84	static inline void debug_spin_lock_after(spinlock_t *lock)
	85	{
	86	lock->owner_cpu = raw_smp_processor_id();
	87	lock->owner = current;
	88	}
	89
	90	static inline void debug_spin_unlock(spinlock_t *lock)
	91	{
	92	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
	93	SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked");
	94	SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
	95	SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
	96	lock, "wrong CPU");
	97	lock->owner = SPINLOCK_OWNER_INIT;
	98	lock->owner_cpu = -1;
	99	}
	100
	101	static void __spin_lock_debug(spinlock_t *lock)
	102	{
fb1c8f93	103	u64 i;
c22f008b CE	104	u64 loops = loops_per_jiffy * HZ;
c22f008b CE	105	int print_once = 1;
fb1c8f93 IM	106
fb1c8f93 IM	107	for (;;) {
c22f008b	108	for (i = 0; i < loops; i++) {
fb1c8f93 IM	109	if (__raw_spin_trylock(&lock->raw_lock))
fb1c8f93 IM	110	return;
e0a60296	111	__delay(1);
fb1c8f93 IM	112	}
	113	/* lockup suspected: */
	114	if (print_once) {
	115	print_once = 0;
51989b9f DJ	116	printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "
51989b9f DJ	117	"%s/%d, %p\n",
bb44f116	118	raw_smp_processor_id(), current->comm,
ba25f9dc	119	task_pid_nr(current), lock);
fb1c8f93	120	dump_stack();
bb81a09e AM	121	#ifdef CONFIG_SMP
	122	trigger_all_cpu_backtrace();
	123	#endif
fb1c8f93 IM	124	}
	125	}
	126	}
	127
	128	void _raw_spin_lock(spinlock_t *lock)
	129	{
	130	debug_spin_lock_before(lock);
	131	if (unlikely(!__raw_spin_trylock(&lock->raw_lock)))
	132	__spin_lock_debug(lock);
	133	debug_spin_lock_after(lock);
	134	}
	135
	136	int _raw_spin_trylock(spinlock_t *lock)
	137	{
	138	int ret = __raw_spin_trylock(&lock->raw_lock);
	139
	140	if (ret)
	141	debug_spin_lock_after(lock);
	142	#ifndef CONFIG_SMP
	143	/*
	144	* Must not happen on UP:
	145	*/
	146	SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
	147	#endif
	148	return ret;
	149	}
	150
	151	void _raw_spin_unlock(spinlock_t *lock)
	152	{
	153	debug_spin_unlock(lock);
	154	__raw_spin_unlock(&lock->raw_lock);
	155	}
	156
	157	static void rwlock_bug(rwlock_t lock, const char msg)
	158	{
9a11b49a IM	159	if (!debug_locks_off())
	160	return;
	161
	162	printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
	163	msg, raw_smp_processor_id(), current->comm,
ba25f9dc	164	task_pid_nr(current), lock);
9a11b49a	165	dump_stack();
fb1c8f93 IM	166	}
	167
	168	#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
	169
72f0b4e2	170	#if 0 /* __write_lock_debug() can lock up - maybe this can too? */
fb1c8f93 IM	171	static void __read_lock_debug(rwlock_t *lock)
fb1c8f93 IM	172	{
fb1c8f93	173	u64 i;
c22f008b CE	174	u64 loops = loops_per_jiffy * HZ;
c22f008b CE	175	int print_once = 1;
fb1c8f93 IM	176
fb1c8f93 IM	177	for (;;) {
c22f008b	178	for (i = 0; i < loops; i++) {
fb1c8f93 IM	179	if (__raw_read_trylock(&lock->raw_lock))
fb1c8f93 IM	180	return;
e0a60296	181	__delay(1);
fb1c8f93 IM	182	}
	183	/* lockup suspected: */
	184	if (print_once) {
	185	print_once = 0;
51989b9f DJ	186	printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
51989b9f DJ	187	"%s/%d, %p\n",
bb44f116 IM	188	raw_smp_processor_id(), current->comm,
bb44f116 IM	189	current->pid, lock);
fb1c8f93 IM	190	dump_stack();
	191	}
	192	}
	193	}
72f0b4e2	194	#endif
fb1c8f93 IM	195
	196	void _raw_read_lock(rwlock_t *lock)
	197	{
	198	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
72f0b4e2	199	__raw_read_lock(&lock->raw_lock);
fb1c8f93 IM	200	}
	201
	202	int _raw_read_trylock(rwlock_t *lock)
	203	{
	204	int ret = __raw_read_trylock(&lock->raw_lock);
	205
	206	#ifndef CONFIG_SMP
	207	/*
	208	* Must not happen on UP:
	209	*/
	210	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
	211	#endif
	212	return ret;
	213	}
	214
	215	void _raw_read_unlock(rwlock_t *lock)
	216	{
	217	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
	218	__raw_read_unlock(&lock->raw_lock);
	219	}
	220
	221	static inline void debug_write_lock_before(rwlock_t *lock)
	222	{
	223	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
	224	RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
	225	RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
	226	lock, "cpu recursion");
	227	}
	228
	229	static inline void debug_write_lock_after(rwlock_t *lock)
	230	{
	231	lock->owner_cpu = raw_smp_processor_id();
	232	lock->owner = current;
	233	}
	234
	235	static inline void debug_write_unlock(rwlock_t *lock)
	236	{
	237	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
	238	RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
	239	RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
	240	lock, "wrong CPU");
	241	lock->owner = SPINLOCK_OWNER_INIT;
	242	lock->owner_cpu = -1;
	243	}
	244
72f0b4e2	245	#if 0 /* This can cause lockups */
fb1c8f93 IM	246	static void __write_lock_debug(rwlock_t *lock)
fb1c8f93 IM	247	{
fb1c8f93	248	u64 i;
c22f008b CE	249	u64 loops = loops_per_jiffy * HZ;
c22f008b CE	250	int print_once = 1;
fb1c8f93 IM	251
fb1c8f93 IM	252	for (;;) {
c22f008b	253	for (i = 0; i < loops; i++) {
fb1c8f93 IM	254	if (__raw_write_trylock(&lock->raw_lock))
fb1c8f93 IM	255	return;
e0a60296	256	__delay(1);
fb1c8f93 IM	257	}
	258	/* lockup suspected: */
	259	if (print_once) {
	260	print_once = 0;
51989b9f DJ	261	printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
51989b9f DJ	262	"%s/%d, %p\n",
bb44f116 IM	263	raw_smp_processor_id(), current->comm,
bb44f116 IM	264	current->pid, lock);
fb1c8f93 IM	265	dump_stack();
	266	}
	267	}
	268	}
72f0b4e2	269	#endif
fb1c8f93 IM	270
	271	void _raw_write_lock(rwlock_t *lock)
	272	{
	273	debug_write_lock_before(lock);
72f0b4e2	274	__raw_write_lock(&lock->raw_lock);
fb1c8f93 IM	275	debug_write_lock_after(lock);
	276	}
	277
	278	int _raw_write_trylock(rwlock_t *lock)
	279	{
	280	int ret = __raw_write_trylock(&lock->raw_lock);
	281
	282	if (ret)
	283	debug_write_lock_after(lock);
	284	#ifndef CONFIG_SMP
	285	/*
	286	* Must not happen on UP:
	287	*/
	288	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
	289	#endif
	290	return ret;
	291	}
	292
	293	void _raw_write_unlock(rwlock_t *lock)
	294	{
	295	debug_write_unlock(lock);
	296	__raw_write_unlock(&lock->raw_lock);
	297	}