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Date: Tue, 2 Dec 2014 12:14:53 -0500
From: Chris Mason <clm@fb.com>
Subject: Re: frequent lockups in 3.18rc4
To: Linus Torvalds <torvalds@linux-foundation.org>
CC: Mike Galbraith <umgwanakikbuti@gmail.com>, Ingo Molnar <mingo@kernel.org>,
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On Tue, Dec 2, 2014 at 11:33 AM, Linus Torvalds 
<torvalds@linux-foundation.org> wrote:
> On Tue, Dec 2, 2014 at 6:13 AM, Mike Galbraith 
> <umgwanakikbuti@gmail.com> wrote:
> 
> At the same time, the whole "incapacitated by the rt throttle long
> enough for the hard lockup detector to trigger" commentary about that
> skip_clock_update issue does make me go "Hmmm..". It would certainly
> explain Dave's incomprehensible watchdog messages..

Dave's first email mentioned that he had panic on softlockup enabled, 
but even with that off the box wasn't recovering.

In my trinity runs here, I've gotten softlockup warnings where the box 
eventually recovered.  I'm wondering if some of the "bad" commits in 
the bisection are really false positives where the box would have been 
able to recover if we'd killed off all the trinity procs and given it 
time to breath.

-chris