Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757297AbZCMAZh (ORCPT ); Thu, 12 Mar 2009 20:25:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756402AbZCMAZF (ORCPT ); Thu, 12 Mar 2009 20:25:05 -0400 Received: from hera.kernel.org ([140.211.167.34]:36695 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755859AbZCMAZD (ORCPT ); Thu, 12 Mar 2009 20:25:03 -0400 Date: Fri, 13 Mar 2009 00:24:31 GMT From: Darren Hart To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, dvhltc@us.ibm.com, hpa@zytor.com, mingo@redhat.com, rusty@rustcorp.com.au, peterz@infradead.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, dvhltc@us.ibm.com, linux-kernel@vger.kernel.org, rusty@rustcorp.com.au, peterz@infradead.org, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20090312075606.9856.88729.stgit@Aeon> References: <20090312075606.9856.88729.stgit@Aeon> Subject: [tip:core/urgent] futex: unlock before returning -EFAULT Message-ID: Git-Commit-ID: 3d7bdf7880ea243f25cddd847ca65475ed627e5f X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 13 Mar 2009 00:24:32 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1892 Lines: 56 Commit-ID: 3d7bdf7880ea243f25cddd847ca65475ed627e5f Gitweb: http://git.kernel.org/tip/3d7bdf7880ea243f25cddd847ca65475ed627e5f Author: Darren Hart AuthorDate: Thu, 12 Mar 2009 00:56:06 -0700 Commit: Ingo Molnar CommitDate: Fri, 13 Mar 2009 01:21:00 +0100 futex: unlock before returning -EFAULT Impact: rt-mutex failure case fix futex_lock_pi can potentially return -EFAULT with the rt_mutex held. This seems like the wrong thing to do as userspace should assume -EFAULT means the lock was not taken. Even if it could figure this out, we'd be leaving the pi_state->owner in an inconsistent state. This patch unlocks the rt_mutex prior to returning -EFAULT to userspace. Build and boot tested on a 4 way Intel x86_64 workstation. Passes basic pthread_mutex and PI tests out of ltp/testcases/realtime. Signed-off-by: Darren Hart Acked-by: Peter Zijlstra Cc: Rusty Russell LKML-Reference: <20090312075606.9856.88729.stgit@Aeon> Signed-off-by: Ingo Molnar --- kernel/futex.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index a66cd2d..7e0a916 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1570,6 +1570,13 @@ retry_locked: } } + /* + * If fixup_pi_state_owner() faulted and was unable to handle the + * fault, unlock it and return the fault to userspace. + */ + if (ret && (rt_mutex_owner(&q.pi_state->pi_mutex) == current)) + rt_mutex_unlock(&q.pi_state->pi_mutex); + /* Unqueue and drop the lock */ unqueue_me_pi(&q); -- 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/