From 78b620ce9e168d08ecfac2f4bb056c511b0601ec Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 31 Aug 2010 02:05:57 +0000
Subject: [PATCH] vhost: stop worker only if created

Its currently illegal to call kthread_stop(NULL)

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/vhost/vhost.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e05557d5299..4b99117f3ec 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -323,7 +323,10 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
 	dev->mm = NULL;
 
 	WARN_ON(!list_empty(&dev->work_list));
-	kthread_stop(dev->worker);
+	if (dev->worker) {
+		kthread_stop(dev->worker);
+		dev->worker = NULL;
+	}
 }
 
 static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
-- 
2.20.1