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authorZhou Chengming <zhouchengming1@huawei.com>2017-08-25 21:49:37 +0800
committerIngo Molnar <mingo@kernel.org>2017-08-29 13:29:29 +0200
commit75e8387685f6c65feb195a4556110b58f852b848 (patch)
tree1c8f8318f1fe76197a2a0d2fcfc53992b1855b30 /kernel/events
parentf12f42acdbb577a12eecfcebbbec41c81505c4dc (diff)
perf/ftrace: Fix double traces of perf on ftrace:function
When running perf on the ftrace:function tracepoint, there is a bug which can be reproduced by: perf record -e ftrace:function -a sleep 20 & perf record -e ftrace:function ls perf script ls 10304 [005] 171.853235: ftrace:function: perf_output_begin ls 10304 [005] 171.853237: ftrace:function: perf_output_begin ls 10304 [005] 171.853239: ftrace:function: task_tgid_nr_ns ls 10304 [005] 171.853240: ftrace:function: task_tgid_nr_ns ls 10304 [005] 171.853242: ftrace:function: __task_pid_nr_ns ls 10304 [005] 171.853244: ftrace:function: __task_pid_nr_ns We can see that all the function traces are doubled. The problem is caused by the inconsistency of the register function perf_ftrace_event_register() with the probe function perf_ftrace_function_call(). The former registers one probe for every perf_event. And the latter handles all perf_events on the current cpu. So when two perf_events on the current cpu, the traces of them will be doubled. So this patch adds an extra parameter "event" for perf_tp_event, only send sample data to this event when it's not NULL. Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: acme@kernel.org Cc: alexander.shishkin@linux.intel.com Cc: huawei.libin@huawei.com Link: http://lkml.kernel.org/r/1503668977-12526-1-git-send-email-zhouchengming1@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ce131d25622a..03ac9c8b02fb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7906,16 +7906,15 @@ void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
}
}
perf_tp_event(call->event.type, count, raw_data, size, regs, head,
- rctx, task);
+ rctx, task, NULL);
}
EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
struct pt_regs *regs, struct hlist_head *head, int rctx,
- struct task_struct *task)
+ struct task_struct *task, struct perf_event *event)
{
struct perf_sample_data data;
- struct perf_event *event;
struct perf_raw_record raw = {
.frag = {
@@ -7929,9 +7928,15 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
perf_trace_buf_update(record, event_type);
- hlist_for_each_entry_rcu(event, head, hlist_entry) {
+ /* Use the given event instead of the hlist */
+ if (event) {
if (perf_tp_event_match(event, &data, regs))
perf_swevent_event(event, count, &data, regs);
+ } else {
+ hlist_for_each_entry_rcu(event, head, hlist_entry) {
+ if (perf_tp_event_match(event, &data, regs))
+ perf_swevent_event(event, count, &data, regs);
+ }
}
/*