Subject: Re: -next: Nov 12 - kernel BUG at kernel/sched.c:7359!

From: Peter Zijlstra <[email-masked]>
Date: Fri, 13 Nov 2009 11:16:08 +0100

On Fri, 2009-11-13 at 15:28 +0530, Gautham R Shenoy wrote:
> On Thu, Nov 12, 2009 at 06:10:31PM +0100, Peter Zijlstra wrote:
> > 
> > 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);
> > 
> 
> How about this ?
> 
> again:
>   	cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
>  	if (!cpu_online(cpu))
>  		cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask);
> 	if (!cpu) {
> 		set_task_affinity(); 
> 		goto again;
> 	}
> > +
> >  	if (cpu != orig_cpu) {
> >  		local_irq_save(flags);
> >  		rq = cpu_rq(cpu);

Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -2376,7 +2376,15 @@ static int try_to_wake_up(struct task_st
 	p->state = TASK_WAKING;
 	__task_rq_unlock(rq);
 
+again:
 	cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
+	if (!cpu_online(cpu))
+		cpu = cpumask_any_and(&p->cpus_allowed, cpu_online_mask);
+	if (cpu >= nr_cpu_ids) {
+		cpuset_cpus_allowed_locked(p, &p->cpus_allowed);
+		goto again;
+	}
+
 	if (cpu != orig_cpu) {
 		rq = cpu_rq(cpu);
 		update_rq_clock(rq);

is what I stuck in and am compiling now.. we'll see what that does.