[PATCH] PPC64: Generic hotplug cpu support

[Andrew Morton]

Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:
>
> > -		if (cpu_is_offline(smp_processor_id()) &&
>  > +		if (cpu_is_offline(_smp_processor_id()) &&
>  >  		    system_state == SYSTEM_RUNNING)
>  >  			cpu_die();
>  >  	}
>  > _
> 
>  This is the idle loop. Is that ever supposed to be preempted ?

Nope, it's a false positive.  We had to do the same in x86's idle loop and
probably others will hit it.