From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
akpm@linux-foundation.org, arnd@arndb.de, christian@brauner.io,
deepa.kernel@gmail.com, ebiederm@xmission.com, elver@google.com,
guro@fb.com, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: cgroup_enable_task_cg_lists && PF_EXITING (Was: KCSAN: data-race in exit_signals / prepare_signal)
Date: Thu, 24 Oct 2019 10:54:27 -0700 [thread overview]
Message-ID: <20191024175427.GC3622521@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20191021142111.GB1339@redhat.com>
Hello, Oleg.
On Mon, Oct 21, 2019 at 04:21:11PM +0200, Oleg Nesterov wrote:
> could you explain the usage of siglock/PF_EXITING in
> cgroup_enable_task_cg_lists() ?
>
> PF_EXITING is protected by cgroup_threadgroup_rwsem, not by
> sighand->siglock.
Yeah, the optimization was added a really long time ago and I'm not
sure it was ever correct. I'm removing it. If this ever becomes a
problem (pretty unlikely), I think the right thing to do is adding a
boot param instead of trying to do this dynamically.
Thanks.
--
tejun
next prev parent reply other threads:[~2019-10-24 17:54 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 10:34 KCSAN: data-race in exit_signals / prepare_signal syzbot
2019-10-21 11:19 ` Christian Brauner
2019-10-21 12:00 ` Oleg Nesterov
2019-10-21 12:15 ` Marco Elver
2019-10-21 13:47 ` Oleg Nesterov
2019-10-21 12:51 ` Christian Brauner
2019-10-21 14:21 ` cgroup_enable_task_cg_lists && PF_EXITING (Was: KCSAN: data-race in exit_signals / prepare_signal) Oleg Nesterov
2019-10-24 17:54 ` Tejun Heo [this message]
2019-10-24 19:03 ` [PATCH cgroup/for-5.5] cgroup: remove cgroup_enable_task_cg_lists() optimization Tejun Heo
2019-10-25 12:56 ` Tejun Heo
2019-10-25 13:33 ` Christian Brauner
2019-10-25 14:13 ` Oleg Nesterov
2019-10-25 14:32 ` Christian Brauner
2019-10-25 15:52 ` Oleg Nesterov
2019-10-25 17:05 ` Christian Brauner
2019-10-28 16:48 ` Oleg Nesterov
2019-10-28 17:30 ` Christian Brauner
2019-10-28 17:46 ` Marco Elver
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