From b118415bfad6d75792a85ac999e25149db8e6919 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 23 Mar 2009 00:18:39 +0100 Subject: [PATCH] tracing/events: don't discard an event after commit When we want to filter an event, the filter test is done after the event is commited to the ring-buffer to be discarded later if needed. But a reader could be reading this event while we are trying to discard it. Other kind of racy events can even happen because the event is commited and can be read and/or consumed. What we want is to discard the event before committing it. Reported-by: Steven Rostedt Signed-off-by: Frederic Weisbecker Cc: Tom Zanussi LKML-Reference: <1237763919-21505-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- kernel/trace/trace_events_stage_3.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_stage_3.h b/kernel/trace/trace_events_stage_3.h index 9a3bd49b52e5..9d2fa78cecca 100644 --- a/kernel/trace/trace_events_stage_3.h +++ b/kernel/trace/trace_events_stage_3.h @@ -222,10 +222,11 @@ static void ftrace_raw_event_##call(proto) \ \ assign; \ \ - trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \ - \ if (call->preds && !filter_match_preds(call, entry)) \ ring_buffer_event_discard(event); \ + \ + trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \ + \ } \ \ static int ftrace_raw_reg_event_##call(void) \ -- 2.20.1