Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758227AbaJDAFq (ORCPT ); Fri, 3 Oct 2014 20:05:46 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45763 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755676AbaJCVxV (ORCPT ); Fri, 3 Oct 2014 17:53:21 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "=?UTF-8?q?Dave=20 \"Trinity\" =20Jones?=" , Thomas Gleixner , Darren Hart , Davidlohr Bueso , Peter Zijlstra Subject: [PATCH 3.16 245/357] futex: Unlock hb->lock in futex_wait_requeue_pi() error path Date: Fri, 3 Oct 2014 14:30:31 -0700 Message-Id: <20141003212940.862527986@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141003212933.458851516@linuxfoundation.org> References: <20141003212933.458851516@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner 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 Signed-off-by: Thomas Gleixner Reviewed-by: Darren Hart Reviewed-by: Davidlohr Bueso Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409112318500.4178@nanos Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- kernel/futex.c | 1 + 1 file changed, 1 insertion(+) --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2628,6 +2628,7 @@ static int futex_wait_requeue_pi(u32 __u * shared futexes. We need to compare the keys: */ if (match_futex(&q.key, &key2)) { + queue_unlock(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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/