From patchwork Wed Aug 31 10:22:37 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 1120582 Received: from smtp1.linux-foundation.org (smtp1.linux-foundation.org [140.211.169.13]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p81KUT3u028773 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for ; Thu, 1 Sep 2011 20:30:51 GMT Received: from daredevil.linux-foundation.org (localhost [127.0.0.1]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p81KSpQK017556; Thu, 1 Sep 2011 13:28:52 -0700 Received: from mail-wy0-f175.google.com (mail-wy0-f175.google.com [74.125.82.175]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p7VAMibJ009261 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=FAIL); Wed, 31 Aug 2011 03:22:46 -0700 Received: by wyf19 with SMTP id 19so375935wyf.6 for ; Wed, 31 Aug 2011 03:22:44 -0700 (PDT) Received: by 10.216.173.198 with SMTP id v48mr204021wel.95.1314786164059; Wed, 31 Aug 2011 03:22:44 -0700 (PDT) Received: from mtj.dyndns.org (apc01.spektrum-hotspot.de [212.77.232.233]) by mx.google.com with ESMTPS id h62sm4183376wee.8.2011.08.31.03.22.42 (version=SSLv3 cipher=OTHER); Wed, 31 Aug 2011 03:22:43 -0700 (PDT) Date: Wed, 31 Aug 2011 12:22:37 +0200 From: Tejun Heo To: "Rafael J. Wysocki" , Oleg Nesterov , Paul Menage Message-ID: <20110831102237.GD2828@mtj.dyndns.org> References: <20110831102100.GA2828@mtj.dyndns.org> <20110831102143.GB2828@mtj.dyndns.org> <20110831102210.GC2828@mtj.dyndns.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110831102210.GC2828@mtj.dyndns.org> User-Agent: Mutt/1.5.21 (2010-09-15) Received-SPF: pass (domain of htejun@gmail.com designates 74.125.82.175 as permitted sender) X-Spam-Status: No, hits=-3.812 required=5 tests=BAYES_00, OSDL_HEADER_SPF_PASS, OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.21 Cc: containers@lists.linux-foundation.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [linux-pm] [PATCH pm-freezer 4/4] freezer: use lock_task_sighand() in fake_signal_wake_up() X-BeenThere: linux-pm@lists.linux-foundation.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: Linux power management List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Thu, 01 Sep 2011 20:30:51 +0000 (UTC) cgroup_freezer calls freeze_task() without holding tasklist_lock and, if the task is exiting, its ->sighand may be gone by the time fake_signal_wake_up() is called. Use lock_task_sighand() instead of accessing ->sighand directly. Signed-off-by: Tejun Heo Reported-by: Oleg Nesterov Cc: "Rafael J. Wysocki" Cc: Paul Menage --- kernel/freezer.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) Index: work/kernel/freezer.c =================================================================== --- work.orig/kernel/freezer.c +++ work/kernel/freezer.c @@ -95,9 +95,10 @@ static void fake_signal_wake_up(struct t { unsigned long flags; - spin_lock_irqsave(&p->sighand->siglock, flags); - signal_wake_up(p, 0); - spin_unlock_irqrestore(&p->sighand->siglock, flags); + if (lock_task_sighand(p, &flags)) { + signal_wake_up(p, 0); + unlock_task_sighand(p, &flags); + } } /**