From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
Paul Menage <paul@paulmenage.org>,
containers@lists.linux-foundation.org,
linux-pm@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH pm-freezer 1/4] cgroup_freezer: fix freezer->state setting bug in freezer_change_state()
Date: Mon, 29 Aug 2011 18:00:31 +0200 [thread overview]
Message-ID: <20110829160031.GB8392@redhat.com> (raw)
In-Reply-To: <20110829140418.GB18871@mtj.dyndns.org>
On 08/29, Tejun Heo wrote:
>
> --- work.orig/kernel/cgroup_freezer.c
> +++ work/kernel/cgroup_freezer.c
> @@ -311,14 +311,14 @@ static int freezer_change_state(struct c
> if (goal_state == freezer->state)
> goto out;
>
> - freezer->state = goal_state;
> -
> switch (goal_state) {
> case CGROUP_THAWED:
> + freezer->state = CGROUP_THAWED;
> atomic_dec(&system_freezing_cnt);
> unfreeze_cgroup(cgroup, freezer);
> break;
> case CGROUP_FROZEN:
> + freezer->state = CGROUP_FREEZING;
At first glance, this is correct. I'll try to recheck.
But,
> atomic_inc(&system_freezing_cnt);
iiuc this becomes wrong... Suppose a user writes "FROZEN" twice,
before freezer->state becomes CGROUP_FROZEN.
I think we should actually fix the "goal_state == freezer->state"
check above.
Oleg.
next prev parent reply other threads:[~2011-08-29 16:04 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-29 14:04 [PATCH pm-freezer 1/4] cgroup_freezer: fix freezer->state setting bug in freezer_change_state() Tejun Heo
2011-08-29 14:05 ` [PATCH pm-freezer 2/4] freezer: set PF_NOFREEZE on a dying task right before TASK_DEAD Tejun Heo
2011-08-29 14:05 ` [PATCH pm-freezer 3/4] freezer: check freezing() before leaving FROZEN state Tejun Heo
2011-08-29 14:06 ` [PATCH pm-freezer 4/4] freezer: use lock_task_sighand() in fake_signal_wake_up() Tejun Heo
2011-08-29 16:36 ` Oleg Nesterov
2011-08-29 16:35 ` [PATCH pm-freezer 3/4] freezer: check freezing() before leaving FROZEN state Oleg Nesterov
2011-08-29 17:12 ` Oleg Nesterov
2011-08-29 17:21 ` Oleg Nesterov
2011-08-29 18:02 ` [PATCH pm-freezer 2/4] freezer: set PF_NOFREEZE on a dying task right before TASK_DEAD Oleg Nesterov
2011-08-29 16:00 ` Oleg Nesterov [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-08-31 10:21 [PATCH pm-freezer 1/4] cgroup_freezer: fix freezer->state setting bug in freezer_change_state() Tejun Heo
2011-08-31 18:08 ` Oleg Nesterov
2011-09-02 0:42 ` Matt Helsley
2011-09-02 2:50 ` Tejun Heo
2011-09-02 16:58 ` Oleg Nesterov
2011-09-02 17:08 ` Tejun Heo
2011-09-02 17:15 ` Oleg Nesterov
2011-09-02 17:31 ` Tejun Heo
2011-09-02 17:30 ` Oleg Nesterov
2011-09-02 18:31 ` Matt Helsley
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