Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932234AbXBWL4F (ORCPT ); Fri, 23 Feb 2007 06:56:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932276AbXBWL4D (ORCPT ); Fri, 23 Feb 2007 06:56:03 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:48515 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932230AbXBWLyr (ORCPT ); Fri, 23 Feb 2007 06:54:47 -0500 From: "Rafael J. Wysocki" To: LKML Subject: [RFC][PATCH 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way Date: Fri, 23 Feb 2007 11:18:06 +0100 User-Agent: KMail/1.9.5 Cc: paulmck@linux.vnet.ibm.com, ego@in.ibm.com, akpm@osdl.org, mingo@elte.hu, vatsa@in.ibm.com, dipankar@in.ibm.com, venkatesh.pallipadi@intel.com, Pavel Machek , "Aneesh Kumar" References: <200702231116.23607.rjw@sisk.pl> In-Reply-To: <200702231116.23607.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200702231118.07629.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1212 Lines: 42 From: Rafael J. Wysocki The reading of PF_BORROWED_MM in is_user_space() without task_lock() is racy. Fix it. Signed-off-by: Rafael J. Wysocki --- kernel/power/process.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) Index: linux-2.6.20-mm2/kernel/power/process.c =================================================================== --- linux-2.6.20-mm2.orig/kernel/power/process.c +++ linux-2.6.20-mm2/kernel/power/process.c @@ -8,6 +8,7 @@ #undef DEBUG +#include #include #include #include @@ -92,7 +93,12 @@ static void cancel_freezing(struct task_ static inline int is_user_space(struct task_struct *p) { - return p->mm && !(p->flags & PF_BORROWED_MM); + int ret; + + task_lock(p); + ret = p->mm && !(p->flags & PF_BORROWED_MM); + task_unlock(p); + return ret; } static unsigned int try_to_freeze_tasks(int freeze_user_space) - 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/