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| author | Zhou Chengming <zhouchengming1@huawei.com> | 2017-08-25 21:49:37 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-29 13:29:29 +0200 |
| commit | 75e8387685f6c65feb195a4556110b58f852b848 (patch) | |
| tree | 1c8f8318f1fe76197a2a0d2fcfc53992b1855b30 /kernel/events | |
| parent | f12f42acdbb577a12eecfcebbbec41c81505c4dc (diff) | |
| download | linux-75e8387685f6c65feb195a4556110b58f852b848.tar.bz2 | |
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.c | 13 |
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); + } } /* |