sched: Fix incorrect sanity check

commit 11854247 upstream

We moved to migrate on wakeup, which means that sleeping tasks could
still be present on offline cpus. Amend the check to only test running
tasks.
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

kernel/cpu.c

@@ -151,7 +151,7 @@ static inline void check_for_tasks(int cpu)
 
 	write_lock_irq(&tasklist_lock);
 	for_each_process(p) {
-		if (task_cpu(p) == cpu &&
+		if (task_cpu(p) == cpu && p->state == TASK_RUNNING &&
 		    (!cputime_eq(p->utime, cputime_zero) ||
 		     !cputime_eq(p->stime, cputime_zero)))
 			printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\