[085/123] sched: Fix hotplug hang

[Greg KH]

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

commit 70f1120527797adb31c68bdc6f1b45e182c342c7 upstream

The hot-unplug kstopmachine usage does a wakeup after
deactivating the cpu, hence we cannot use cpu_active()
here but must rely on the good olde online.

Reported-by: Sachin Sant <sachinp@xxxxxxxxxx>
Reported-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Tested-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
LKML-Reference: <1261326987.4314.24.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Mike Galbraith <efault@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 kernel/sched.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2376,7 +2376,7 @@ int select_task_rq(struct task_struct *p
 	 *   not worry about this generic constraint ]
 	 */
 	if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
-		     !cpu_active(cpu)))
+		     !cpu_online(cpu)))
 		cpu = select_fallback_rq(task_cpu(p), p);
 
 	return cpu;


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