From: Tejun Heo <tj@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Imran Khan <imran.f.khan@oracle.com>,
Xuewen Yan <xuewen.yan@unisoc.com>,
syzbot <syzbot+29d3a3b4d86c8136ad9e@syzkaller.appspotmail.com>,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH] cgroup: Add missing cpus_read_lock() to cgroup_attach_task_all()
Date: Thu, 25 Aug 2022 07:44:36 -1000 [thread overview]
Message-ID: <Ywe1BAeUsJV7ZXzF@slm.duckdns.org> (raw)
In-Reply-To: <cb0b22e1-0d55-cb06-7401-37581c18169b@I-love.SAKURA.ne.jp>
On Thu, Aug 25, 2022 at 05:38:38PM +0900, Tetsuo Handa wrote:
> syzbot is hitting percpu_rwsem_assert_held(&cpu_hotplug_lock) warning at
> cpuset_attach() [1], for commit 4f7e7236435ca0ab ("cgroup: Fix
> threadgroup_rwsem <-> cpus_read_lock() deadlock") missed that
> cpuset_attach() is also called from cgroup_attach_task_all().
> Add cpus_read_lock() like what cgroup_procs_write_start() does.
>
> Link: https://syzkaller.appspot.com/bug?extid=29d3a3b4d86c8136ad9e [1]
> Reported-by: syzbot <syzbot+29d3a3b4d86c8136ad9e@syzkaller.appspotmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Fixes: 4f7e7236435ca0ab ("cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock")
Applied to cgroup/for-6.0-fixes and sent pull request.
> Waiting for test result from syzbot. Should we remove "static" from
> cgroup_attach_lock() and call from cgroup_attach_task_all() ?
Yeah, that probably is better. Can you spin up a follow up patch?
Thanks.
--
tejun
prev parent reply other threads:[~2022-08-25 17:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 16:36 [syzbot] WARNING in cpuset_attach syzbot
2022-08-24 20:32 ` syzbot
2022-08-25 8:38 ` [PATCH] cgroup: Add missing cpus_read_lock() to cgroup_attach_task_all() Tetsuo Handa
2022-08-25 17:44 ` Tejun Heo [this message]
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