Re: 2.6.22-rc1: Broken suspend on SMP with tifm

From: Oleg Nesterov
Date: Sun May 13 2007 - 17:54:23 EST


On 05/13, Rafael J. Wysocki wrote:
>
> On Sunday, 13 May 2007 23:34, Oleg Nesterov wrote:
> > On 05/13, Rafael J. Wysocki wrote:
> > >
> > > @@ -819,20 +843,31 @@ static int __devinit workqueue_cpu_callb
> > >
> > > +
> > > + case CPU_DEAD_FROZEN:
> > > + if (wq->freezeable) {
> > > + take_over_work(wq, cpu);
> > > + thaw_process(cwq->thread);
> >
> > Suppose that PF_NOFREEZE task T does flush_workqueue(), and CPU 1 has pending
> > works. T does flush_cpu_workqueue(0), CPU_DEAD_FROZEN moves works from CPU 1
> > to CPU 0, T does flush_cpu_workqueue(1) and finds nothing.
>
> I don't think this is possible, because we've acquired workqueue_mutex in
> _cpu_down().

Yes, we did... but flush_workqueue() doesn't take it?

Oleg.

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