From: Tejun Heo <tj@kernel.org>
To: Shida Zhang <starzhangzsd@gmail.com>
Cc: lizefan.x@bytedance.com, hannes@cmpxchg.org,
zhangshida@kylinos.cn, linux-kernel@vger.kernel.org,
cgroups@vger.kernel.org
Subject: Re: [PATCH] cgroup: fix potential null pointer risk
Date: Tue, 17 May 2022 07:07:37 -1000 [thread overview]
Message-ID: <YoPWWfoZ+6PrHuJl@slm.duckdns.org> (raw)
In-Reply-To: <20220517073106.1704628-1-zhangshida@kylinos.cn>
On Tue, May 17, 2022 at 03:31:06PM +0800, Shida Zhang wrote:
> We previously assumed 'parent' could be null,
> so null pointer judgment should be added.
>
> Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
> ---
> kernel/cgroup/cgroup.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index adb820e98f24..7f230b0ab644 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -5701,7 +5701,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
> }
> spin_unlock_irq(&css_set_lock);
>
> - cgroup1_check_for_release(parent);
> + if (parent)
> + cgroup1_check_for_release(parent);
The function is never called for a root cgroup. The parent check up above in
the same function is superflous. So, maybe remove that?
Thanks.
--
tejun
next prev parent reply other threads:[~2022-05-17 17:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-17 7:31 Shida Zhang
2022-05-17 17:07 ` Tejun Heo [this message]
2022-05-18 1:04 ` Stephen Zhang
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