--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1649,6 +1649,8 @@ static int set_bit_to_user(int nr, void __user *addr)
 	r = get_user_pages_fast(log, 1, 1, &page);
 	if (r < 0)
 		return r;
+	if (r == 0)
+		return -EFAULT;
 	BUG_ON(r != 1);
 	base = kmap_atomic(page);
 	set_bit(bit, base);