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authorThomas Gleixner <tglx@linutronix.de>2014-09-11 23:44:35 +0200
committerJiri Slaby <jslaby@suse.cz>2014-09-15 18:19:38 +0200
commit70279f38568703022d4790d382d1f6462f8b6383 (patch)
tree0a62c3151a4c15a30c49b2ccaead4d63ecfa413a /kernel
parentbbcd86fa91e60af29c3de9a38aa28c314468cc5f (diff)
futex: Unlock hb->lock in futex_wait_requeue_pi() error path
commit 13c42c2f43b19aab3195f2d357db00d1e885eaa8 upstream. futex_wait_requeue_pi() calls futex_wait_setup(). If futex_wait_setup() succeeds it returns with hb->lock held and preemption disabled. Now the sanity check after this does: if (match_futex(&q.key, &key2)) { ret = -EINVAL; goto out_put_keys; } which releases the keys but does not release hb->lock. So we happily return to user space with hb->lock held and therefor preemption disabled. Unlock hb->lock before taking the exit route. Reported-by: Dave "Trinity" Jones <davej@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409112318500.4178@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/futex.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index f94695c9d38b..e4b9b60e25b1 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2465,6 +2465,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
* shared futexes. We need to compare the keys:
*/
if (match_futex(&q.key, &key2)) {
+ queue_unlock(&q, hb);
ret = -EINVAL;
goto out_put_keys;
}