From: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Frederic Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Mandeep Singh Baines
<msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
Li Zefan <lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Containers
<containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
KAMEZAWA Hiroyuki
<kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>,
Paul Menage <paul-inf54ven1CmVyaH7bEyXVA@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
"Paul E. McKenney"
<paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Subject: Re: Q: cgroup: Questions about possible issues in cgroup locking
Date: Thu, 22 Dec 2011 16:30:04 +0100 [thread overview]
Message-ID: <20111222153004.GA30522@redhat.com> (raw)
In-Reply-To: <20111221200422.GJ17668@somewhere>
On 12/21, Frederic Weisbecker wrote:
>
> On Wed, Dec 21, 2011 at 11:24:13AM -0800, Mandeep Singh Baines wrote:
> >
> > If you call exec from a thread other than g, g is now unlinked. So
> > "t != g" will always be true. If you then pthread_create, you now
> > have two threads so "t != __prev" will also always be true. So
> > you now have an infinite loop.
>
> Oh you're right.
>
> But then we can't use t != t->group_leader because that assumes while_each_thread()
> started on the leader.
Yes, this can't work.
Besides, we need more burriers to rely on the ->group_leader check.
See http://marc.info/?t=127688987300002
in particular, http://marc.info/?l=linux-kernel&m=127714242731448
I think this should work, but then we should do something with the
users like zap_threads().
Oleg.
next prev parent reply other threads:[~2011-12-22 15:30 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-21 3:43 Q: cgroup: Questions about possible issues in cgroup locking Frederic Weisbecker
2011-12-21 13:08 ` Oleg Nesterov
[not found] ` <20111221130848.GA19679-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-12-21 17:56 ` Frederic Weisbecker
2011-12-21 19:01 ` Mandeep Singh Baines
[not found] ` <20111221190102.GE13529-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-21 19:08 ` Frederic Weisbecker
2011-12-21 19:24 ` Mandeep Singh Baines
[not found] ` <20111221192413.GF13529-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-21 20:04 ` Frederic Weisbecker
2011-12-22 15:30 ` Oleg Nesterov [this message]
[not found] ` <20111222153004.GA30522-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-01-04 19:36 ` Mandeep Singh Baines
[not found] ` <20120104193614.GF9511-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-01-06 15:23 ` Oleg Nesterov
[not found] ` <20120106152356.GA23995-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-01-06 18:25 ` Mandeep Singh Baines
[not found] ` <20120106182535.GJ9511-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-01-11 16:07 ` Oleg Nesterov
[not found] ` <20120111160730.GA24556-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-01-12 0:31 ` Mandeep Singh Baines
[not found] ` <20120112003102.GB9511-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-01-12 17:07 ` Oleg Nesterov
[not found] ` <20120112170728.GA25717-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-01-12 17:57 ` Mandeep Singh Baines
[not found] ` <20120112175725.GD9511-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-01-13 15:20 ` Oleg Nesterov
[not found] ` <20120113152010.GA19215-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-01-13 18:27 ` Mandeep Singh Baines
[not found] ` <20120113182750.GD18166-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-01-14 17:36 ` Oleg Nesterov
[not found] ` <20120114173648.GA32543-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-01-18 23:17 ` Mandeep Singh Baines
2012-01-19 15:45 ` Oleg Nesterov
[not found] ` <20120119154522.GA14058-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-01-19 18:18 ` Mandeep Singh Baines
[not found] ` <20120119181803.GU18166-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-01-20 15:06 ` Oleg Nesterov
2012-03-20 19:34 ` Oleg Nesterov
[not found] ` <20120320193414.GA21277-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-03-21 18:59 ` Mandeep Singh Baines
[not found] ` <20120321185955.GK27051-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-03-23 17:51 ` Oleg Nesterov
2011-12-21 17:59 ` Frederic Weisbecker
2011-12-21 18:11 ` Oleg Nesterov
[not found] ` <20111221181101.GA3092-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-12-21 18:23 ` Frederic Weisbecker
2012-02-01 16:28 ` Frederic Weisbecker
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