linux-kernel - [PATCH] perf: fix put

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Message-Id: <1424954613-5034-1-git-send-email-chianglungyu@gmail.com>
Date:	Thu, 26 Feb 2015 20:43:33 +0800
From:	Leon Yu <chianglungyu@...il.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	Leon Yu <chianglungyu@...il.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] perf: fix put_event() ctx leak

Commit a83fe28e2e45 ("perf: Fix put_event() ctx lock") changed lock logic in
put_event() by replacing mutex_lock_nested() with perf_event_ctx_lock_nested(),
but didn't fix subsequent mutex_unlock() with correct counterpart,
perf_event_ctx_unlock(). ctx is thus leaked as a result of incremented
refcount in perf_event_ctx_lock_nested().

Signed-off-by: Leon Yu <chianglungyu@...il.com>
Fixes: a83fe28e2e45 ("perf: Fix put_event() ctx lock")
---
 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);
 }
-- 
2.3.1

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