From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754428Ab1IBS2U (ORCPT ); Fri, 2 Sep 2011 14:28:20 -0400 Received: from mail-pz0-f42.google.com ([209.85.210.42]:48944 "EHLO mail-pz0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754379Ab1IBS2Q (ORCPT ); Fri, 2 Sep 2011 14:28:16 -0400 From: Tejun Heo To: oleg@redhat.com, matthltc@us.ibm.com, rjw@sisk.pl, paul@paulmenage.org Cc: containers@lists.linux-foundation.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 4/6] freezer: use lock_task_sighand() in fake_signal_wake_up() 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> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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); + } } /** -- 1.7.6