Re: [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM

Marc Zyngier
2011-05-26T16:19:45Z

On Thu, 2011-05-26 at 18:09 +0200, Peter Zijlstra wrote:
> On Thu, 2011-05-26 at 17:59 +0200, Peter Zijlstra wrote:
> > On Thu, 2011-05-26 at 17:45 +0200, Oleg Nesterov wrote:
> > > Stupid question. Can't we fix this problem if we do
> > >
> > > - if (p == current)
> > > + if (cpu == raw_smp_processor_id())
> > >
> > > ?
> > >
> > > I forgot the rules... but iirc task_cpu(p) can't be changed under us?
> >
> > Easy enough to test.. brain gave out again,. hold on ;-)
>
> The below seems to run all-right so far, I'll let it run for a while.

Doesn't look very good here. The serial console basically locks up as
soon as the system gets busy, even if the kernel compilation seem to
progress at a decent pace.

M.

--
Reality is an implementation detail.