From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Frederic Weisbecker
<fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: Is not locking task_lock in cgroup_fork() safe?
Date: Mon, 8 Oct 2012 11:01:38 +0900 [thread overview]
Message-ID: <20121008020138.GA4188@localhost> (raw)
In-Reply-To: <20121008020000.GB2575@localhost>
On Mon, Oct 08, 2012 at 11:00:00AM +0900, Tejun Heo wrote:
> 7e381b0eb1 ("cgroup: Drop task_lock(parent) on cgroup_fork()") removed
> task_lock from cgroup_fork citing that current->cgroups can't change
> due to threadgroup_change locking; however, threadgroup_change locking
> is used only during CLONE_THREAD forking. If @current is forking a
> new process, there's nothing preventing someone else to migrate the
> parent while forking is in progress and delete the css_set it
> currently is using. Am I confused somewhere?
Also, please note that task_lock is likely to be hot on local CPU at
that point and avoiding it there might not really buy much.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-10-08 2:01 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-08 2:00 Is not locking task_lock in cgroup_fork() safe? Tejun Heo
2012-10-08 2:01 ` Tejun Heo [this message]
2012-10-08 5:46 ` Li Zefan
2012-10-08 5:46 ` Li Zefan
[not found] ` <507268AA.8050509-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-10-08 6:57 ` Tejun Heo
2012-10-08 6:57 ` Tejun Heo
2012-10-16 19:34 ` Tejun Heo
[not found] ` <20121016193428.GE16166-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-17 7:26 ` Li Zefan
2012-10-17 7:26 ` Li Zefan
2012-10-08 12:58 ` Frederic Weisbecker
2012-10-08 12:58 ` Frederic Weisbecker
2012-10-08 12:48 ` Frederic Weisbecker
[not found] ` <CAFTL4hzXWtzp7megsCAEuak5=_2SWmp9age-+wrpyQAU4BRZ0w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-16 19:33 ` Tejun Heo
[not found] ` <20121016193341.GD16166-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-18 14:50 ` Frederic Weisbecker
2012-10-18 14:50 ` Frederic Weisbecker
2012-10-18 14:50 ` Frederic Weisbecker
[not found] ` <CAFTL4hzo_w7HTgC9ApTk113X8WdZSpV+D+VSEe=604YEJFmKsg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-18 20:07 ` Tejun Heo
2012-10-18 20:07 ` Tejun Heo
[not found] ` <20121018200705.GG13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-18 20:53 ` Frederic Weisbecker
2012-10-18 20:53 ` Frederic Weisbecker
[not found] ` <CAFTL4hy7g4e11OUOyoihrEU8hiVgZoV1=141UtUpj9a72SNs_Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-19 0:38 ` Tejun Heo
2012-10-19 0:38 ` Tejun Heo
[not found] ` <20121019003835.GE13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 0:58 ` Tejun Heo
2012-10-19 0:58 ` Tejun Heo
[not found] ` <20121019005801.GF13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 8:50 ` Li Zefan
2012-10-19 8:50 ` Li Zefan
2012-10-19 8:50 ` Li Zefan
2012-10-19 0:38 ` Tejun Heo
2012-10-08 12:48 ` Frederic Weisbecker
2012-10-19 0:59 ` [PATCH cgroup/for-3.7-fixes 1/2] Revert "cgroup: Remove task_lock() from cgroup_post_fork()" Tejun Heo
[not found] ` <20121019005922.GG13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 8:51 ` Li Zefan
2012-10-19 13:35 ` Frederic Weisbecker
[not found] ` <CAFTL4hz82==b3ioSMhbKzh0CN1ivR7RQMKKMFFWu5PHPjg=Bfg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-19 19:38 ` Tejun Heo
2012-10-19 19:38 ` Tejun Heo
[not found] ` <20121019193808.GL13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 19:44 ` Frederic Weisbecker
2012-10-19 19:44 ` Frederic Weisbecker
2012-10-19 19:44 ` Frederic Weisbecker
[not found] ` <CAFTL4hwQ6Ntn5GJwj=jiO2p3GdwhEMp0MyR8dgUj_Lx0U4kNqg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-19 21:07 ` Tejun Heo
2012-10-19 21:07 ` Tejun Heo
[not found] ` <20121019210738.GA1180-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-20 18:21 ` Frederic Weisbecker
2012-10-20 18:21 ` Frederic Weisbecker
[not found] ` <CAFTL4hy+vrvJKrc1Y2FW44k=LBi72H=34337xALpbtG_3u5O7w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-20 18:23 ` Frederic Weisbecker
2012-10-20 18:23 ` Frederic Weisbecker
2012-10-20 22:37 ` Tejun Heo
2012-10-20 22:37 ` Tejun Heo
[not found] ` <20121020223709.GA5626-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-22 9:30 ` Frederic Weisbecker
2012-10-22 9:30 ` Frederic Weisbecker
2012-10-22 9:30 ` Frederic Weisbecker
2012-10-19 21:07 ` Tejun Heo
2012-10-19 13:35 ` Frederic Weisbecker
2012-10-19 0:59 ` Tejun Heo
2012-10-19 0:59 ` [PATCH cgroup/for-3.7-fixes 2/2] Revert "cgroup: Drop task_lock(parent) on cgroup_fork()" Tejun Heo
[not found] ` <20121019005951.GH13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 8:51 ` Li Zefan
2012-10-19 8:51 ` Li Zefan
2012-10-19 13:45 ` Frederic Weisbecker
2012-10-19 13:45 ` Frederic Weisbecker
2012-10-19 0:59 ` Tejun Heo
-- strict thread matches above, loose matches on Subject: below --
2012-10-08 2:00 Is not locking task_lock in cgroup_fork() safe? Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121008020138.GA4188@localhost \
--to=tj-dgejt+ai2ygdnm+yrofe0a@public.gmane.org \
--cc=cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org \
--cc=fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
--cc=lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.