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| author | Thomas Gleixner <tglx@linutronix.de> | 2009-10-04 09:34:17 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-10-05 21:08:14 +0200 |
| commit | eaaea8036d0261d87d7072c5bc88c7ea730c18ac (patch) | |
| tree | 07bbd53bdc9a47d86ca667f3171c3b7ebf1ac07c /kernel/futex.c | |
| parent | d014e8894dfc523dd9d2f2a17b6dcb94facea810 (diff) | |
| download | lwn-eaaea8036d0261d87d7072c5bc88c7ea730c18ac.tar.gz lwn-eaaea8036d0261d87d7072c5bc88c7ea730c18ac.zip | |
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>
Diffstat (limited to 'kernel/futex.c')
| -rw-r--r-- | kernel/futex.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 463af2efa512..1e176f3ab26c 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)) { |