When 'stacktrace' trigger is used for event tracing, it should skip 4
functions instead of 3. Otherwise it'll contain ftrace_raw_event_XXX
like below:
# echo stacktrace > events/sched/sched_switch/trigger
# tail trace
=> rcu_gp_kthread
=> kthread
=> ret_from_fork
ksoftirqd/0-3 [000] d..3 53.343993: <stack trace>
=> ftrace_raw_event_sched_switch
=> __schedule
=> schedule
=> smpboot_thread_fn
=> kthread
=> ret_from_fork
Reported-by: Minchan Kim <[email protected]>
Cc: Tom Zanussi <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
---
kernel/trace/trace_events_trigger.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_events_trigger.c
b/kernel/trace/trace_events_trigger.c
index 8712df9decb4..c58fbdd3053e 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -965,12 +965,13 @@ static __init int register_trigger_snapshot_cmd(void) {
return 0; }
#ifdef CONFIG_STACKTRACE
/*
- * Skip 3:
+ * Skip 4:
* stacktrace_trigger()
* event_triggers_post_call()
+ * ftrace_event_buffer_commit()
* ftrace_raw_event_xxx()
*/
-#define STACK_SKIP 3
+#define STACK_SKIP 4
static void
stacktrace_trigger(struct event_trigger_data *data)
--
2.3.3
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