From patchwork Fri Sep 2 18:27:48 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 1122922 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 p82IV14A015960 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for ; Fri, 2 Sep 2011 18:31:22 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 p82ITC3M010779; Fri, 2 Sep 2011 11:29:12 -0700 Received: from mail-pz0-f47.google.com (mail-pz0-f47.google.com [209.85.210.47]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p82ISGe6010089 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=FAIL); Fri, 2 Sep 2011 11:28:17 -0700 Received: by pzk2 with SMTP id 2so4380491pzk.20 for ; Fri, 02 Sep 2011 11:28:16 -0700 (PDT) Received: by 10.68.0.106 with SMTP id 10mr2168371pbd.453.1314988096697; Fri, 02 Sep 2011 11:28:16 -0700 (PDT) Received: from localhost.localdomain ([121.167.223.83]) by mx.google.com with ESMTPS id i1sm11753361pbe.1.2011.09.02.11.28.13 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 02 Sep 2011 11:28:16 -0700 (PDT) From: Tejun Heo To: oleg@redhat.com, matthltc@us.ibm.com, rjw@sisk.pl, paul@paulmenage.org Date: Sat, 3 Sep 2011 03:27:48 +0900 Message-Id: <1314988070-12244-5-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.6 In-Reply-To: <1314988070-12244-1-git-send-email-tj@kernel.org> References: <1314988070-12244-1-git-send-email-tj@kernel.org> Received-SPF: pass (localhost is always allowed.) X-Spam-Status: No, hits=-4.156 required=5 tests=AWL, BAYES_00, OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf-20110901g X-Scanned-By: MIMEDefang 2.63 on 140.211.169.21 X-Scanned-By: MIMEDefang 2.63 on 140.211.169.51 Cc: Tejun Heo , containers@lists.linux-foundation.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [linux-pm] [PATCH 4/6] 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: , MIME-Version: 1.0 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]); Fri, 02 Sep 2011 18:31:22 +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 files changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/freezer.c b/kernel/freezer.c index ebee1ab..9846133 100644 --- a/kernel/freezer.c +++ b/kernel/freezer.c @@ -93,9 +93,10 @@ static void fake_signal_wake_up(struct task_struct *p) { 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); + } } /**