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From: Tejun Heo <tj@kernel.org>
To: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	Al Viro <viro@zeniv.linux.org.uk>,
	Zefan Li <lizefan.x@bytedance.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	stable@vger.kernel.org,
	Richard Purdie <richard.purdie@linuxfoundation.org>
Subject: Re: [PATCH] cgroup1: fix leaked context root causing sporadic NULL deref in LTP
Date: Wed, 16 Jun 2021 11:23:34 -0400	[thread overview]
Message-ID: <YMoXdljfOFjoVO93@slm.duckdns.org> (raw)
In-Reply-To: <20210616125157.438837-1-paul.gortmaker@windriver.com>

Hello,

On Wed, Jun 16, 2021 at 08:51:57AM -0400, Paul Gortmaker wrote:
> A fix would be to not leave the stale reference in fc->root as follows:
> 
>    --------------
>                   dput(fc->root);
>   +               fc->root = NULL;
>                   deactivate_locked_super(sb);
>    --------------
> 
> ...but then we are just open-coding a duplicate of fc_drop_locked() so we
> simply use that instead.

As this is unlikely to be a real-world problem both in probability and
circumstances, I'm applying this to cgroup/for-5.14 instead of
cgroup/for-5.13-fixes.

Thanks.

-- 
tejun

  reply	other threads:[~2021-06-16 15:23 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16 12:51 [PATCH] cgroup1: fix leaked context root causing sporadic NULL deref in LTP Paul Gortmaker
2021-06-16 15:23 ` Tejun Heo [this message]
2021-06-30 16:10   ` Mark Brown
2021-06-30 22:31     ` Richard Purdie
2021-07-01 12:11       ` Mark Brown
2021-07-01 12:43         ` Richard Purdie
2021-07-12 17:34 ` Tejun Heo

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