From: Suren Baghdasaryan <surenb@google.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>,
"cgroups mailinglist" <cgroups@vger.kernel.org>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Li Zefan" <lizefan@huawei.com>,
alex.shi@linux.alibaba.com, "Roman Gushchin" <guro@fb.com>,
kernel-team <kernel-team@android.com>,
"JeiFeng Lee" <linger.lee@mediatek.com>,
linux-arm-kernel@lists.infradead.org,
LKML <linux-kernel@vger.kernel.org>,
linux-kselftest@vger.kernel.org,
linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com,
shuah@kernel.org, "Tom Cherry" <tomcherry@google.com>
Subject: Re: [PATCH 2/3] cgroup: Iterate tasks that did not finish do_exit()
Date: Fri, 17 Jan 2020 10:41:29 -0800 [thread overview]
Message-ID: <CAJuCfpFqEUVFXsjD8XcCKsGXKTf72r0Ek5_1yqu_k5UZAssKTw@mail.gmail.com> (raw)
In-Reply-To: <20200117172806.GK2677547@devbig004.ftw2.facebook.com>
On Fri, Jan 17, 2020 at 9:28 AM Tejun Heo <tj@kernel.org> wrote:
>
> 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.
Tested-by: Suren Baghdasaryan <surenb@google.com>
>
> Yeah, this looks fine to me. Any chance you can order this before the
> clean up so that we can mark it for -stable.
>
+1 for reordering. Makes it easier to backport.
Thanks,
Suren.
> Thanks.
>
> --
> tejun
>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com.
>
next prev parent reply other threads:[~2020-01-17 18:41 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
2020-01-17 15:15 ` [PATCH 2/3] cgroup: Iterate tasks that did not finish do_exit() Michal Koutný
2020-01-17 17:28 ` Tejun Heo
2020-01-17 18:41 ` Suren Baghdasaryan [this message]
2020-01-20 14:56 ` Michal Koutný
2020-01-24 11:40 ` [PATCH v2 0/3] " Michal Koutný
2020-01-24 11:40 ` [PATCH v2 1/3] " Michal Koutný
2020-01-24 22:56 ` Suren Baghdasaryan
2020-02-05 17:27 ` Suren Baghdasaryan
2020-02-12 22:03 ` Tejun Heo
2020-01-24 11:40 ` [PATCH v2 2/3] cgroup: Clean up css_set task traversal Michal Koutný
2020-01-24 11:40 ` [PATCH v2 3/3] kselftest/cgroup: add cgroup destruction test Michal Koutný
2020-02-12 22:10 ` Tejun Heo
2020-01-17 15:15 ` [PATCH " 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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