From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Aleksa Sarai <cyphar@cyphar.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Li Zefan <lizefan@huawei.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH?] race between cgroup_subsys->fork() and cgroup_migrate()
Date: Thu, 26 Nov 2015 16:36:09 +0100 [thread overview]
Message-ID: <20151126153609.GA23581@redhat.com> (raw)
In-Reply-To: <20151125195410.GD14240@htj.duckdns.org>
On 11/25, Tejun Heo wrote:
>
> On Wed, Nov 25, 2015 at 02:51:38PM -0500, Tejun Heo wrote:
> > Sounds perfect. As this needs to go through -stable, can you please
> > resend the patch with proper description and SOB? Please also update
> > the now incorrect comment in can_attach.
OK, will do tomorrow (sorry, can't do today).
> Ooh, the patch triggers RCU warning from task_css(). It's spurious
> and I think the right thing to do at least for now is using
> task_css_check() and explain what's going on.
WARN_ON() in pids_fork() I guess. Thanks. I didn't expect you will actually
apply this patch, I didn't even try to compile it ;)
Plus this patch forgets to unconditionalize another threadgroup_change_end()
in the error path of copy_process().
Again, if we do this, we can make other cleanups/simplifications. For example,
we can kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] in copy_process().
But I see another email from you, will reply in a minute.
Oleg.
next prev parent reply other threads:[~2015-11-26 15:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-25 16:34 [PATCH?] race between cgroup_subsys->fork() and cgroup_migrate() Oleg Nesterov
2015-11-25 19:51 ` Tejun Heo
2015-11-25 19:54 ` Tejun Heo
2015-11-25 20:40 ` Tejun Heo
2015-11-26 16:01 ` Oleg Nesterov
2015-11-26 15:36 ` Oleg Nesterov [this message]
2015-11-26 23:35 ` Aleksa Sarai
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