From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Sasha Levin <sasha.levin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Cc: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] cgroup: missing rcu read lock around task_css_set
Date: Tue, 4 Mar 2014 14:47:41 -0500 [thread overview]
Message-ID: <20140304194741.GA2204@htj.dyndns.org> (raw)
In-Reply-To: <53160B6D.8020501-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
On Tue, Mar 04, 2014 at 12:20:45PM -0500, Sasha Levin wrote:
> >Hrm... there is a PF_EXITING check there already:
> >
> > #define task_css_set_check(task, __c) \
> > rcu_dereference_check((task)->cgroups, \
> > lockdep_is_held(&cgroup_mutex) || \
> > lockdep_is_held(&css_set_rwsem) || \
> > ((task)->flags & PF_EXITING) || (__c))
> >
> >I see it's not happening on Linus's master so I'll run a bisection to figure out what broke it.
>
> Hi Tejun,
>
> It bisects down to your patch: "cgroup: drop task_lock() protection
> around task->cgroups". I'll look into it later unless it's obvious
> to you.
Hmmm... maybe I'm confused and PF_EXITING is not set there and
task_lock was what held off the lockdep warning. Confused....
Thanks.
--
tejun
next prev parent reply other threads:[~2014-03-04 19:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-02 3:00 [PATCH] cgroup: missing rcu read lock around task_css_set Sasha Levin
[not found] ` <1393729211-937-1-git-send-email-sasha.levin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2014-03-03 22:33 ` Tejun Heo
[not found] ` <20140303223327.GB26523-9pTldWuhBndy/B6EtB590w@public.gmane.org>
2014-03-03 22:43 ` Sasha Levin
[not found] ` <5315057F.3030602-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2014-03-03 22:45 ` Tejun Heo
2014-03-03 22:48 ` Sasha Levin
[not found] ` <20140303224505.GE26523-9pTldWuhBndy/B6EtB590w@public.gmane.org>
2014-03-03 23:00 ` Sasha Levin
[not found] ` <53150989.70307-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2014-03-04 17:20 ` Sasha Levin
[not found] ` <53160B6D.8020501-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2014-03-04 19:47 ` Tejun Heo [this message]
[not found] ` <20140304194741.GA2204-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2014-03-05 0:57 ` Li Zefan
[not found] ` <53167662.5000801-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2014-03-27 15:35 ` Sasha Levin
[not found] ` <5334452D.4080200-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2014-03-28 2:48 ` Li Zefan
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