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Subject: Re: [PATCH] sched: fix race in schedule
From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>, Ingo Molnar <mingo@elte.hu>,
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       hpj@urpla.net, stable <stable@kernel.org>
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Date: Fri, 14 Mar 2008 23:57:14 +0100
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On Fri, 2008-03-14 at 23:47 +0100, Dmitry Adamushko wrote:
> On 14/03/2008, Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> wrote:
> >
> > [ ... ]
> >
> >  >> But maybe there is something esle that would be exposed by the
> >  >> 'rq->curr = rq->idle' manipulation... I can't provide examples right
> >  >> now though (I need to think on it).
> >  >
> >  > I share your concerns, I don't really like it either. Just spewing out
> >  > ideas here - bad ideas it seems :-/
> >  >
> >  > Ingo also suggested moving the balance calls right before
> >  > deactivate_task(), but that gives a whole other set of head-aches.
> >  >
> >
> >
> > Well, what will we do about this issue?
> >  I see you're thinking to fix inconsistency in scheduler, right?
> >  I agree about it.
> >
> >  However, I don't think it's good to remain this issue long time in
> >  the -stable kernel.
> >
> >  Could you please let me know what I can do?
> 
> IMHO, the safest solution for the time being (and esp. for -stable)
> would be to proceed with Hiroshi's patch. It looks safe and it does
> fix a real problem.

Agreed