3.2.64-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Gleixner <[email protected]> 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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Darren Hart <[email protected]> Reviewed-by: Davidlohr Bueso <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409112318500.4178@nanos Signed-off-by: Thomas Gleixner <[email protected]> [bwh: Backported to 3.2: queue_unlock() takes two parameters] Signed-off-by: Ben Hutchings <[email protected]> --- kernel/futex.c | 1 + 1 file changed, 1 insertion(+) --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2460,6 +2460,7 @@ static int futex_wait_requeue_pi(u32 __u * shared futexes. We need to compare the keys: */ if (match_futex(&q.key, &key2)) { + queue_unlock(&q, hb); ret = -EINVAL; goto out_put_keys; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
