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authorThomas Gleixner <tglx@linutronix.de>2009-10-04 09:34:17 +0200
committerIngo Molnar <mingo@elte.hu>2009-10-05 21:08:14 +0200
commiteaaea8036d0261d87d7072c5bc88c7ea730c18ac (patch)
tree07bbd53bdc9a47d86ca667f3171c3b7ebf1ac07c
parentd014e8894dfc523dd9d2f2a17b6dcb94facea810 (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> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Darren Hart <dvhltc@us.ibm.com> Cc: stable-2.6.31 <stable@kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/futex.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 463af2efa51..1e176f3ab26 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -916,8 +916,8 @@ 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)) {