From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH 1/2] device_cgroup: fix RCU usage
Date: Tue, 6 Nov 2012 12:29:17 -0800
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To: Serge Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
Cc: Aristeu Rozanski <aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>, "Serge E. Hallyn" <serge.hallyn-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org>, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org

On Tue, Nov 06, 2012 at 11:48:41AM -0600, Serge Hallyn wrote:
> Quoting Tejun Heo (tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org):
> > dev_cgroup->exceptions is protected with devcgroup_mutex for writes
> > and RCU for reads; however, RCU usage isn't correct.
> > 
> > * dev_exception_clean() doesn't use RCU variant of list_del() and
> >   kfree().  The function can race with may_access() and may_access()
> >   may end up dereferencing already freed memory.  Use list_del_rcu()
> >   and kfree_rcu() instead.
> > 
> > * may_access() may be called only with RCU read locked but doesn't use
> >   RCU safe traversal over ->exceptions.  Use list_for_each_entry_rcu().
> > 
> > Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> > Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > Cc: Aristeu Rozanski <aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
> > Cc: Serge E. Hallyn <serge.hallyn-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org>
> 
> Acked-by: Serge E. Hallyn <serge.hallyn-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org>

Thanks, applied to cgroup/for-3.7-fixes.

-- 
tejun