From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754291Ab1IBS2H (ORCPT ); Fri, 2 Sep 2011 14:28:07 -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 S1754057Ab1IBS2F (ORCPT ); Fri, 2 Sep 2011 14:28:05 -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 1/6] cgroup_freezer: fix freezer->state setting bug in freezer_change_state() Date: Sat, 3 Sep 2011 03:27:45 +0900 Message-Id: <1314988070-12244-2-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 d02f52811d0e "cgroup_freezer: prepare for removal of TIF_FREEZE" moved setting of freezer->state into freezer_change_state(); unfortunately, while doing so, when it's beginning to freeze tasks, it sets the state to CGROUP_FROZEN instead of CGROUP_FREEZING ending up skipping the whole freezing state. Fix it. -v2: Oleg pointed out that re-freezing FROZEN cgroup could increment system_freezing_cnt. Fixed. -v3: Matt pointed out that setting CGROUP_FROZEN always invoked try_to_freeze_cgroup() regardless of the current state. Patch updated such that the actual freeze/thaw operations are always performed on state changes. This shouldn't make any difference unless something is broken. Signed-off-by: Tejun Heo Reported-by: Oleg Nesterov Cc: Paul Menage Cc: "Rafael J. Wysocki" Cc: Matt Helsley --- kernel/cgroup_freezer.c | 14 +++++++------- 1 files changed, 7 insertions(+), 7 deletions(-) diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c index 4e82525..56a457a 100644 --- a/kernel/cgroup_freezer.c +++ b/kernel/cgroup_freezer.c @@ -308,24 +308,24 @@ static int freezer_change_state(struct cgroup *cgroup, spin_lock_irq(&freezer->lock); update_if_frozen(cgroup, freezer); - if (goal_state == freezer->state) - goto out; - - freezer->state = goal_state; switch (goal_state) { case CGROUP_THAWED: - atomic_dec(&system_freezing_cnt); + if (freezer->state != CGROUP_THAWED) + atomic_dec(&system_freezing_cnt); + freezer->state = CGROUP_THAWED; unfreeze_cgroup(cgroup, freezer); break; case CGROUP_FROZEN: - atomic_inc(&system_freezing_cnt); + if (freezer->state == CGROUP_THAWED) + atomic_inc(&system_freezing_cnt); + freezer->state = CGROUP_FREEZING; retval = try_to_freeze_cgroup(cgroup, freezer); break; default: BUG(); } -out: + spin_unlock_irq(&freezer->lock); return retval; -- 1.7.6