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>