an 'I' will be displayed on the same line as the function that
can be overridden.
+ If a non ftrace trampoline is attached (BPF) a 'D' will be displayed.
+ Note, normal ftrace trampolines can also be attached, but only one
+ "direct" trampoline can be attached to a given function at a time.
+
+ Some architectures can not call direct trampolines, but instead have
+ the ftrace ops function located above the function entry point. In
+ such cases an 'O' will be displayed.
+
+ If a function had either the "ip modify" or a "direct" call attached to
+ it in the past, a 'M' will be shown. This flag is never cleared. It is
+ used to know if a function was every modified by the ftrace infrastructure,
+ and can be used for debugging.
+
If the architecture supports it, it will also show what callback
is being directly called by the function. If the count is greater
than 1 it most likely will be ftrace_ops_list_func().
its address will be printed as well as the function that the
trampoline calls.
+ touched_functions:
+
+ This file contains all the functions that ever had a function callback
+ to it via the ftrace infrastructure. It has the same format as
+ enabled_functions but shows all functions that have every been
+ traced.
+
+ To see any function that has every been modified by "ip modify" or a
+ direct trampoline, one can perform the following command:
+
+ grep ' M ' /sys/kernel/tracing/touched_functions
+
function_profile_enabled:
When set it will enable all functions with either the function
Stack trace
-----------
Since the kernel has a fixed sized stack, it is important not to
-waste it in functions. A kernel developer must be conscience of
+waste it in functions. A kernel developer must be conscious of
what they allocate on the stack. If they add too much, the system
can be in danger of a stack overflow, and corruption will occur,
usually leading to a system panic.
* CALL_OPS - the record can use callsite-specific ops
* CALL_OPS_EN - the function is set up to use callsite-specific ops
* TOUCHED - A callback was added since boot up
+ * MODIFIED - The function had IPMODIFY or DIRECT attached to it
*
* When a new ftrace_ops is registered and wants a function to save
* pt_regs, the rec->flags REGS is set. When the function has been
FTRACE_FL_CALL_OPS = (1UL << 22),
FTRACE_FL_CALL_OPS_EN = (1UL << 21),
FTRACE_FL_TOUCHED = (1UL << 20),
+ FTRACE_FL_MODIFIED = (1UL << 19),
};
- #define FTRACE_REF_MAX_SHIFT 20
+ #define FTRACE_REF_MAX_SHIFT 19
#define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
#define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX)
#define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
#define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
-static inline unsigned long get_lock_parent_ip(void)
+static __always_inline unsigned long get_lock_parent_ip(void)
{
unsigned long addr = CALLER_ADDR0;
#include "trace_stat.h"
/* Flags that do not get reset */
- #define FTRACE_NOCLEAR_FLAGS (FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED)
+ #define FTRACE_NOCLEAR_FLAGS (FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED | \
+ FTRACE_FL_MODIFIED)
#define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
rec->flags &= ~FTRACE_FL_TRAMP_EN;
}
+ /* Keep track of anything that modifies the function */
+ if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
+ rec->flags |= FTRACE_FL_MODIFIED;
+
if (flag & FTRACE_FL_DIRECT) {
/*
* If there's only one user (direct_ops helper)
if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
struct ftrace_ops *ops;
- seq_printf(m, " (%ld)%s%s%s%s",
+ seq_printf(m, " (%ld)%s%s%s%s%s",
ftrace_rec_count(rec),
rec->flags & FTRACE_FL_REGS ? " R" : " ",
rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
rec->flags & FTRACE_FL_DIRECT ? " D" : " ",
- rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ");
+ rec->flags & FTRACE_FL_CALL_OPS ? " O" : " ",
+ rec->flags & FTRACE_FL_MODIFIED ? " M " : " ");
if (rec->flags & FTRACE_FL_TRAMP_EN) {
ops = ftrace_find_tramp_ops_any(rec);
if (ops) {
* and returns 1 in case we resolved all the requested symbols,
* 0 otherwise.
*/
-static int kallsyms_callback(void *data, const char *name,
- struct module *mod, unsigned long addr)
+static int kallsyms_callback(void *data, const char *name, unsigned long addr)
{
struct kallsyms_data *args = data;
const char **sym;
unsigned long flags;
if (in_nmi()) {
- internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
- internal_trace_puts("*** snapshot is being ignored ***\n");
+ trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
+ trace_array_puts(tr, "*** snapshot is being ignored ***\n");
return;
}
if (!tr->allocated_snapshot) {
- internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
- internal_trace_puts("*** stopping trace here! ***\n");
- tracing_off();
+ trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
+ trace_array_puts(tr, "*** stopping trace here! ***\n");
+ tracer_tracing_off(tr);
return;
}
/* Note, snapshot can not be used when the tracer uses it */
if (tracer->use_max_tr) {
- internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
- internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
+ trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
+ trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
return;
}
tracefs_remove(tr->dir);
free_percpu(tr->last_func_repeats);
free_trace_buffers(tr);
+ clear_tracing_err_log(tr);
for (i = 0; i < tr->nr_topts; i++) {
kfree(tr->topts[i].topts);
tr->buffer_percent = 50;
- trace_create_file("buffer_percent", TRACE_MODE_READ, d_tracer,
+ trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
tr, &buffer_percent_fops);
create_trace_options_dir(tr);
void __init ftrace_boot_snapshot(void)
{
+#ifdef CONFIG_TRACER_MAX_TRACE
struct trace_array *tr;
- if (snapshot_at_boot) {
- tracing_snapshot();
- internal_trace_puts("** Boot snapshot taken **\n");
- }
+ if (!snapshot_at_boot)
+ return;
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
- if (tr == &global_trace)
+ if (!tr->allocated_snapshot)
continue;
- trace_array_puts(tr, "** Boot snapshot taken **\n");
+
tracing_snapshot_instance(tr);
+ trace_array_puts(tr, "** Boot snapshot taken **\n");
}
+#endif
}
void __init early_trace_init(void)
projects / J-linux.git / commitdiff