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Subject: Re: [BUG stable, 2.6.32.27] sched: delayed cleanup of user_struct
From: Mike Galbraith <efault@gmx.de>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>,
        Kay Sievers <kay.sievers@vrfy.org>,
        Dhaval Giani <dhaval@linux.vnet.ibm.com>,
        Greg Kroah-Hartman <gregkh@suse.de>, linux-kernel@vger.kernel.org,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
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Date: Mon, 10 Jan 2011 18:07:50 +0100
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On Mon, 2011-01-10 at 15:19 +0100, Oleg Nesterov wrote:
> On 01/10, Stefan Priebe - Profihost AG wrote:
> >
> >>> You can find the logs here:
> >>> http://pastebin.com/hNd15E8K
> >>
> >> Good. Sadly, I didn't see this trace before...
> >>
> >> 	kernel BUG at kernel/workqueue.c:287!
> >>
> >> this matches "INIT_DELAYED_WORK() can corrupt the pending work" I
> >> mentioned.
> > Sorry to ask this but this could also be "workarounded" by disabled
> > GROUP_SCHED? Or is this another thing?
> 
> Yes, this looks like the same thing.
> 
> But let me repeat, today I looked at this code for the first time ;)
> 
> > Will wait if greg or anybody else can tell
> > us something about it.
> 
> Indeed.

I'd be inclined to just shoot USER_SCHED, since it's dead upstream.  I'm
putting a small backport series together, and could add that to the mix.

	-Mike