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From: Tejun Heo <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: Zefan Li <lizefan.x@bytedance.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cgroup: Protect css->cgroup write under css_set_lock
Date: Wed, 3 Jul 2024 08:59:41 -1000	[thread overview]
Message-ID: <ZoWfnS6NvEoNckGO@slm.duckdns.org> (raw)
In-Reply-To: <20240703185229.1849423-1-longman@redhat.com>

On Wed, Jul 03, 2024 at 02:52:29PM -0400, Waiman Long wrote:
> The writing of css->cgroup associated with the cgroup root in
> rebind_subsystems() is currently protected only by cgroup_mutex.
> However, the reading of css->cgroup in both proc_cpuset_show() and
> proc_cgroup_show() is protected just by css_set_lock. That makes the
> readers susceptible to racing problems like data tearing or caching.
> It is also a problem that can be reported by KCSAN.
> 
> This can be fixed by using READ_ONCE() and WRITE_ONCE() to access
> css->cgroup. Alternatively, the writing of css->cgroup can be moved
> under css_set_lock as well which is done by this patch.
> 
> Signed-off-by: Waiman Long <longman@redhat.com>

Applied to cgroup/for-6.10-fixes.

Thanks.

-- 
tejun

      reply	other threads:[~2024-07-03 18:59 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-03 18:52 Waiman Long
2024-07-03 18:59 ` Tejun Heo [this message]

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