[PATCH] rcutorture: Make stall-tasks directly exit when rcutorture tests end

[Zqiang]

When the rcutorture tests start to exit, the rcu_torture_cleanup() is
invoked to stop kthreads and release resources, if the stall-task
kthreads exist, cpu-stall has started and the rcutorture.stall_cpu
is set to a larger value, the rcu_torture_cleanup() will be blocked
for a long time and the hung-task may occur, this commit therefore
add kthread_should_stop() to the loop of cpu-stall operation, when
rcutorture tests ends, no need to wait for cpu-stall to end, exit
directly.

Signed-off-by: Zqiang <qiang.zhang1211@xxxxxxxxx>
---
 kernel/rcu/rcutorture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 3f9c3766f52b..6a3cd6ed8b25 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2490,7 +2490,7 @@ static int rcu_torture_stall(void *args)
 		pr_alert("%s start on CPU %d.\n",
 			  __func__, raw_smp_processor_id());
 		while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
-				    stop_at))
+				    stop_at) && !kthread_should_stop())
 			if (stall_cpu_block) {
 #ifdef CONFIG_PREEMPTION
 				preempt_schedule();
-- 
2.17.1