[tip:perf/urgent] perf: Fix context leak in put_event()

[tip-bot for Leon Yu <tipbot@zytor.com>]

Commit-ID:  d415a7f1c1a8406b22d95b943c66a5b73a37bc19
Gitweb:     http://git.kernel.org/tip/d415a7f1c1a8406b22d95b943c66a5b73a37bc19
Author:     Leon Yu <chianglungyu@gmail.com>
AuthorDate: Thu, 26 Feb 2015 20:43:33 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 13 Mar 2015 10:02:18 +0100

perf: Fix context leak in put_event()

Commit:

  a83fe28e2e45 ("perf: Fix put_event() ctx lock")

changed the locking logic in put_event() by replacing mutex_lock_nested()
with perf_event_ctx_lock_nested(), but didn't fix the subsequent
mutex_unlock() with a correct counterpart, perf_event_ctx_unlock().

Contexts are thus leaked as a result of incremented refcount
in perf_event_ctx_lock_nested().

Signed-off-by: Leon Yu <chianglungyu@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Fixes: a83fe28e2e45 ("perf: Fix put_event() ctx lock")
Link: http://lkml.kernel.org/r/1424954613-5034-1-git-send-email-chianglungyu@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f04daab..453ef61 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3591,7 +3591,7 @@ static void put_event(struct perf_event *event)
 	ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
 	WARN_ON_ONCE(ctx->parent_ctx);
 	perf_remove_from_context(event, true);
-	mutex_unlock(&ctx->mutex);
+	perf_event_ctx_unlock(event, ctx);
 
 	_free_event(event);
 }