Date: Sat, 13 Dec 2014 09:27:51 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Jones <davej@redhat.com>, Chris Mason <clm@fb.com>,
        Mike Galbraith <umgwanakikbuti@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        =?iso-8859-1?Q?D=E2niel?= Fraga <fragabr@gmail.com>,
        Sasha Levin <sasha.levin@oracle.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: frequent lockups in 3.18rc4
Message-ID: <20141213082751.GA1526@gmail.com>
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* Ingo Molnar <mingo@kernel.org> wrote:

> 
> * Linus Torvalds <torvalds@linux-foundation.org> wrote:
> 
> > On Fri, Dec 12, 2014 at 10:54 AM, Dave Jones <davej@redhat.com> wrote:
> >
> > >
> > > Something that's still making me wonder if it's some kind of 
> > > hardware problem is the non-deterministic nature of this bug.
> > 
> > I'd expect it to be a race condition, though. Which can easily 
> > cause these kinds of issues, and the timing will be pretty 
> > random even if the load is very regular.
> > 
> > And we know that the scheduler has an integer overflow under 
> > Sasha's loads, although I didn't hear anything from Ingo and 
> > friends about it. Ingo/Peter, you were cc'd on that report, 
> > where at least one of the multiplcations in wake_affine() ended 
> > up overflowing..
> 
> Just to make sure, is there any other wake_affine report other 
> than the one in this thread? (I tried a wake_affine full text 
> search on my inbox and didn't find anything that appeared 
> relevant.)

Found the report from Sasha:

    sched: odd values for effective load calculations

right?

Thanks,

	Ingo
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