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>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e05557d52999..4b99117f3ecd 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)