[tip:perf/core] perf: Validate locking assumption

From: tip-bot for Peter Zijlstra
Date: Thu May 08 2014 - 06:45:54 EST


Commit-ID: 63342411efd2d9350ad405205da036cd45ed1640
Gitweb: http://git.kernel.org/tip/63342411efd2d9350ad405205da036cd45ed1640
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 5 May 2014 11:49:16 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 7 May 2014 13:44:18 +0200

perf: Validate locking assumption

Document and validate the locking assumption of event_sched_in().

Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-sybq1publ9xt5no77cwvi0eo@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 819ffc0..0de1997 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1678,6 +1678,8 @@ event_sched_in(struct perf_event *event,
u64 tstamp = perf_event_time(event);
int ret = 0;

+ lockdep_assert_held(&ctx->lock);
+
if (event->state <= PERF_EVENT_STATE_OFF)
return 0;

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