From: Tejun Heo <tj@kernel.org>
To: cgroups@vger.kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
Mike Galbraith <efault@gmx.de>,
kernel-team@fb.com
Subject: Re: [PATCH cgroup/for-4.10-fixes] cgroup/pids: remove spurious suspicious RCU usage warning
Date: Mon, 6 Mar 2017 15:12:00 -0500 [thread overview]
Message-ID: <20170306201200.GI19696@htj.duckdns.org> (raw)
In-Reply-To: <20170301203907.GF3662@htj.duckdns.org>
On Wed, Mar 01, 2017 at 03:39:07PM -0500, Tejun Heo wrote:
> pids_can_fork() is special in that the css association is guaranteed
> to be stable throughout the function and thus doesn't need RCU
> protection around task_css access. When determining the css to charge
> the pid, task_css_check() is used to override the RCU sanity check.
>
> While adding a warning message on fork rejection from pids limit,
> 135b8b37bd91 ("cgroup: Add pids controller event when fork fails
> because of pid limit") incorrectly added a task_css access which is
> neither RCU protected or explicitly annotated. This triggers the
> following suspicious RCU usage warning when RCU debugging is enabled.
Applied to cgroup/for-4.11-fixes.
--
tejun
prev parent reply other threads:[~2017-03-06 20:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-20 10:15 [cgroups] suspicious rcu_dereference_check() usage! Mike Galbraith
2017-03-01 17:44 ` Tejun Heo
2017-03-01 17:57 ` Mike Galbraith
2017-03-01 20:39 ` [PATCH cgroup/for-4.10-fixes] cgroup/pids: remove spurious suspicious RCU usage warning Tejun Heo
2017-03-06 20:12 ` Tejun Heo [this message]
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