diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2014-09-11 23:44:35 +0200 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2014-12-01 18:02:30 +0800 |
| commit | 40ee8d0faf83eb55d4829796a28dacf48519caec (patch) | |
| tree | 0395a72bf583d469f1a2552716faf0dc7841b0dc /kernel | |
| parent | e393942b1628770467481935738fd214566fe7bb (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>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409112318500.4178@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[lizf: Backported to 3.4: queue_unlock() takes two parameters]
Signed-off-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/futex.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 9396b7b853f7..41dfb1866f95 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2460,6 +2460,7 @@ 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; } |