From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760966AbbA1EQr (ORCPT ); Tue, 27 Jan 2015 23:16:47 -0500 Received: from mail.kernel.org ([198.145.29.136]:37840 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760890AbbA1EQn (ORCPT ); Tue, 27 Jan 2015 23:16:43 -0500 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Zefan Li Subject: [PATCH 3.4 36/91] futex: Unlock hb->lock in futex_wait_requeue_pi() error path Date: Wed, 28 Jan 2015 12:07:19 +0800 Message-Id: <1422418236-12852-72-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1422418050-12581-1-git-send-email-lizf@kernel.org> References: <1422418050-12581-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner 3.4.105-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 [lizf: Backported to 3.4: queue_unlock() takes two parameters] Signed-off-by: Zefan Li --- kernel/futex.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/futex.c b/kernel/futex.c index 9396b7b..41dfb18 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; } -- 1.9.1