From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: "Michal Koutný" <mkoutny-IBi9RG/b67k@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org,
guro-b10kYP2dOMg@public.gmane.org,
kernel-team-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org,
linger.lee-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kselftest-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
tomcherry-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org
Subject: Re: [PATCH 2/3] cgroup: Iterate tasks that did not finish do_exit()
Date: Fri, 17 Jan 2020 09:28:06 -0800 [thread overview]
Message-ID: <20200117172806.GK2677547@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20200117151533.12381-3-mkoutny-IBi9RG/b67k@public.gmane.org>
On Fri, Jan 17, 2020 at 04:15:32PM +0100, Michal Koutný wrote:
> PF_EXITING is set earlier than actual removal from css_set when a task
> is exitting. This can confuse cgroup.procs readers who see no PF_EXITING
> tasks, however, rmdir is checking against css_set membership so it can
> transitionally fail with EBUSY.
>
> Fix this by listing tasks that weren't unlinked from css_set active
> lists.
> It may happen that other users of the task iterator (without
> CSS_TASK_ITER_PROCS) spot a PF_EXITING task before cgroup_exit(). This
> is equal to the state before commit c03cd7738a83 ("cgroup: Include dying
> leaders with live threads in PROCS iterations") but it may be reviewed
> later.
Yeah, this looks fine to me. Any chance you can order this before the
clean up so that we can mark it for -stable.
Thanks.
--
tejun
next prev parent reply other threads:[~2020-01-17 17:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 4:36 [PATCH 1/2] cgroup: allow deletion of cgroups containing only dying processes Suren Baghdasaryan
2020-01-16 4:36 ` [PATCH 2/2] kselftest/cgroup: add cgroup destruction test Suren Baghdasaryan
2020-01-17 15:15 ` [PATCH 0/3] cgroup: Iterate tasks that did not finish do_exit() Michal Koutný
2020-01-17 15:15 ` [PATCH 1/3] cgroup: Unify css_set task lists Michal Koutný
2020-01-17 16:59 ` Tejun Heo
[not found] ` <20200117151533.12381-1-mkoutny-IBi9RG/b67k@public.gmane.org>
2020-01-17 15:15 ` [PATCH 2/3] cgroup: Iterate tasks that did not finish do_exit() Michal Koutný
[not found] ` <20200117151533.12381-3-mkoutny-IBi9RG/b67k@public.gmane.org>
2020-01-17 17:28 ` Tejun Heo [this message]
[not found] ` <20200117172806.GK2677547-LpCCV3molIbIZ9tKgghJQw2O0Ztt9esIQQ4Iyu8u01E@public.gmane.org>
2020-01-17 18:41 ` Suren Baghdasaryan
[not found] ` <CAJuCfpFqEUVFXsjD8XcCKsGXKTf72r0Ek5_1yqu_k5UZAssKTw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-01-20 14:56 ` Michal Koutný
2020-01-24 11:40 ` [PATCH v2 0/3] " Michal Koutný
[not found] ` <20200124114017.8363-1-mkoutny-IBi9RG/b67k@public.gmane.org>
2020-01-24 11:40 ` [PATCH v2 1/3] " Michal Koutný
2020-01-24 22:56 ` Suren Baghdasaryan
[not found] ` <CAJuCfpGjC=YwY=oNnYFNDp2nCuR9YhSU95=xbbeoDEheemte+Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-02-05 17:27 ` Suren Baghdasaryan
[not found] ` <20200124114017.8363-2-mkoutny-IBi9RG/b67k@public.gmane.org>
2020-02-12 22:03 ` Tejun Heo
2020-01-24 11:40 ` [PATCH v2 3/3] kselftest/cgroup: add cgroup destruction test Michal Koutný
[not found] ` <20200124114017.8363-4-mkoutny-IBi9RG/b67k@public.gmane.org>
2020-02-12 22:10 ` Tejun Heo
2020-01-24 11:40 ` [PATCH v2 2/3] cgroup: Clean up css_set task traversal Michal Koutný
2020-01-17 15:15 ` [PATCH 3/3] kselftest/cgroup: add cgroup destruction test Michal Koutný
2020-01-17 17:30 ` [PATCH 0/3] cgroup: Iterate tasks that did not finish do_exit() Suren Baghdasaryan
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