[PATCH v2 1/2] lib/lwq: fix potential kthread_stop() hang in test

[Josh Law <objecting@objecting.org>]

From: Josh Law <objecting@objecting.org>

Check kthread_should_stop() in lwq_exercise()'s wait_var_event()
so the thread can exit cleanly when kthread_stop() is called while
the queue is empty.

Signed-off-by: Josh Law <objecting@objecting.org>
---
 lib/lwq.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/lwq.c b/lib/lwq.c
index c1e11ba6f254..1fd2ed612c75 100644
--- a/lib/lwq.c
+++ b/lib/lwq.c
@@ -86,7 +86,10 @@ static int lwq_exercise(void *qv)
 	struct tnode *t;
 
 	for (cnt = 0; cnt < 10000; cnt++) {
-		wait_var_event(q, (t = lwq_dequeue(q, struct tnode, n)) != NULL);
+		wait_var_event(q, (t = lwq_dequeue(q, struct tnode, n)) != NULL ||
+			       kthread_should_stop());
+		if (!t)
+			break;
 		t->c++;
 		if (lwq_enqueue(&t->n, q))
 			wake_up_var(q);
-- 
2.34.1