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authorThomas Gleixner <tglx@linutronix.de>2009-10-04 09:34:17 +0200
committerThomas Gleixner <tglx@linutronix.de>2009-10-05 12:36:05 +0200
commita374cc63356bdf15b2c350dfa3729de6717e8caf (patch)
treec0a95b7bb91f8ef36ac4314b28c0c4dd20c7bd9b
parentf0f436465d7f6ff40694503d085d226159e93f5c (diff)
futex: Fix locking imbalance
Rich reported a lock imbalance in the futex code. (http://bugzilla.kernel.org/show_bug.cgi?id=14288) It's caused by the displacement of the retry_private label in futex_wake_op(). The code unlocks the hash bucket locks in the error handling path and retries without locking them again which makes the next unlock fail. Move retry_private so we lock the hash bucket locks when we retry. Reported-by: Rich Ercolany <rercola@acm.jhu.edu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Darren Hart <dvhltc@us.ibm.com> Cc: stable-2.6.31 <stable@kernel.org>
-rw-r--r--kernel/futex.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 4705d89205a1..4ac78d9da6fe 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -959,8 +959,8 @@ retry:
hb1 = hash_futex(&key1);
hb2 = hash_futex(&key2);
- double_lock_hb(hb1, hb2);
retry_private:
+ double_lock_hb(hb1, hb2);
op_ret = futex_atomic_op_inuser(op, uaddr2);
if (unlikely(op_ret < 0)) {