From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: -next: Nov 12 - kernel BUG at kernel/sched.c:7359!
Date: Fri, 13 Nov 2009 10:06:13 +0100
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To: Sachin Sant <sachinp@in.ibm.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Stephen Rothwell <sfr@canb.auug.org.au>, linux-next@vger.kernel.org, Ingo Molnar <mingo@elte.hu>, Mike Galbraith <efault@gmx.de>, Gautham R Shenoy <ego@in.ibm.com>

On Fri, 2009-11-13 at 14:30 +0530, Sachin Sant wrote:
> Peter Zijlstra wrote:
> > So what we need to do is make the whole of select_task_rq_fair()
> > cpu_online/active_mask aware, or give up and simply punt:
> >
> > diff --git a/kernel/sched.c b/kernel/sched.c
> > index 1f2e99d..62df61c 100644
> > --- a/kernel/sched.c
> > +++ b/kernel/sched.c
> > @@ -2377,6 +2377,9 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
> >  	task_rq_unlock(rq, &flags);
> >
> >  	cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
> > +	if (!cpu_active(cpu))
> > +		cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask);
> > +
> >  	if (cpu != orig_cpu) {
> >  		local_irq_save(flags);
> >  		rq = cpu_rq(cpu);
> >
> >
> > Something I think Mike also tried and didn't deadlock for him..
> >
> > Sachin, Mike, could you try the above snippet and verify if it does
> > indeed solve your respective issues?
> >   
> Unfortunately the above patch made things worse. With this patch
> the machine failed to boot with following oops

Ugh, more head scratching for me then..

Thanks for testing.