From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org, Roman Gushchin <guro@fb.com>,
Richard Purdie <richard.purdie@linuxfoundation.org>,
Bruce Ashfield <bruce.ashfield@gmail.com>
Subject: Re: [PATCH] cgroup: freezer: call cgroup_enter_frozen() with preemption disabled in ptrace_stop()
Date: Fri, 11 Oct 2019 09:52:13 -0700 [thread overview]
Message-ID: <20191011165213.GB18794@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20191009150230.GB12511@redhat.com>
On Wed, Oct 09, 2019 at 05:02:30PM +0200, Oleg Nesterov wrote:
> ptrace_stop() does preempt_enable_no_resched() to avoid the preemption,
> but after that cgroup_enter_frozen() does spin_lock/unlock and this adds
> another preemption point.
>
> Reported-and-tested-by: Bruce Ashfield <bruce.ashfield@gmail.com>
> Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer")
> Cc: stable@vger.kernel.org # v5.2+
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Applied to cgroup/for-5.4-fixes.
Thanks.
--
tejun
prev parent reply other threads:[~2019-10-11 16:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-01 16:14 ptrace/strace and freezer oddities and v5.2+ kernels Bruce Ashfield
2019-10-02 2:01 ` Roman Gushchin
2019-10-02 4:18 ` Bruce Ashfield
2019-10-02 18:19 ` Roman Gushchin
2019-10-02 21:59 ` Bruce Ashfield
2019-10-04 0:09 ` Roman Gushchin
2019-10-07 12:54 ` Bruce Ashfield
2019-10-07 20:11 ` Bruce Ashfield
2019-10-07 23:27 ` Roman Gushchin
2019-10-08 12:13 ` Bruce Ashfield
2019-10-08 12:36 ` Oleg Nesterov
2019-10-08 12:58 ` Bruce Ashfield
2019-10-08 17:27 ` Roman Gushchin
2019-10-09 15:02 ` [PATCH] cgroup: freezer: call cgroup_enter_frozen() with preemption disabled in ptrace_stop() Oleg Nesterov
2019-10-09 15:21 ` Roman Gushchin
2019-10-11 16:52 ` Tejun Heo [this message]
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