From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Li Zefan <lizefan@huawei.com>,
cgroups@vger.kernel.org
Subject: Re: lockdep trace from prepare_bprm_creds
Date: Thu, 7 Mar 2013 11:33:42 -0800 [thread overview]
Message-ID: <20130307193342.GA3209@htj.dyndns.org> (raw)
In-Reply-To: <20130307183213.GA18022@redhat.com>
On Thu, Mar 07, 2013 at 07:32:14PM +0100, Oleg Nesterov wrote:
> On 03/07, Tejun Heo wrote:
> >
> > On Thu, Mar 07, 2013 at 10:01:39AM -0800, Tejun Heo wrote:
> > >
> > > Another possibility is moving cgroup_lock outside threadgroup_lock(),
> > > which was impossible before because of cgroup_lock abuses in specific
> > > controller implementations but most of that have been updated and we
> > > should now be pretty close to being able to make cgroup_lock outer to
> > > most other locks. Appending a completely untested patch below.
> >
> > This probably doesn't help as the dependency involves i_mutex.
>
> Confused... why?
Maybe I'm confused. We still have i_mutex -> cgroup_lock from the
mount path. The original deadlock was cred_mutex -> i_mutex
vs. i_mutex -> cgroup_mutex -> cred_mutex. The patch changes the
latter to i_mutex -> cgroup_mutex and cred_mutex -> cgroup_mutex.
Gosh, it's confusing, yeah, we might be okay.
--
tejun
prev parent reply other threads:[~2013-03-07 19:33 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 22:36 Dave Jones
2013-03-07 17:25 ` Oleg Nesterov
2013-03-07 18:01 ` Tejun Heo
2013-03-07 18:03 ` Tejun Heo
2013-03-07 19:12 ` Oleg Nesterov
2013-03-07 19:38 ` Tejun Heo
2013-03-09 2:11 ` Li Zefan
2013-03-09 3:29 ` Tejun Heo
2013-03-09 7:47 ` Li Zefan
2013-03-09 20:00 ` [PATCH 0/1] do not abuse ->cred_guard_mutex in threadgroup_lock() Oleg Nesterov
2013-03-09 20:01 ` [PATCH 1/1] " Oleg Nesterov
2013-03-09 20:15 ` Tejun Heo
2013-03-11 1:50 ` Li Zefan
2013-03-21 16:21 ` [PATCH] " Oleg Nesterov
2013-03-21 22:06 ` Andrew Morton
2013-03-22 13:20 ` Oleg Nesterov
2013-03-19 22:02 ` [PATCH cgroup/for-3.10] cgroup: make cgroup_mutex outer to threadgroup_lock Tejun Heo
2013-03-20 0:58 ` Li Zefan
2013-03-20 15:03 ` Tejun Heo
2013-03-20 18:35 ` Oleg Nesterov
2013-03-20 18:42 ` Tejun Heo
2013-03-21 16:17 ` Oleg Nesterov
2013-03-07 18:21 ` lockdep trace from prepare_bprm_creds Tejun Heo
2013-03-07 18:32 ` Oleg Nesterov
2013-03-07 19:33 ` Tejun Heo [this message]
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