Date: Thu, 11 Apr 2013 09:45:29 +0200
From: Stanislaw Gruszka <sgruszka@redhat.com>
To: Dave Hansen <dave@sr71.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Subject: Re: sched/cputime: sig->prev_stime underflow
Message-ID: <20130411074529.GA1629@redhat.com>
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On Mon, Apr 08, 2013 at 08:57:16AM -0700, Dave Hansen wrote:
> On 04/04/2013 04:41 PM, Frederic Weisbecker wrote:
> > Does this patch fix the issue for you?
> > https://lkml.org/lkml/2013/4/4/112
> 
> Nope, that doesn't seem to make a difference.  I'm still seeing the
> underflow.  I'm pretty sure it's already gone to hell by the time it
> gets in to the loop that's patched there.

Perhaps this is glich introduced by commit 
62188451f0d63add7ad0cd2a1ae269d600c1663d "cputime: Avoid multiplication
overflow on utime scaling" . Could you try to revert it and see if that
helps. If it does not, can you check if problem happen on 3.8 ?

Stanislaw
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