[PATCH] vhost: fix virtqueue access lock check for handlers

[David Marchand]

As the vhost library may receive a request for an unsupported request,
it is necessary to check msg_handler before checking if locking queue
pairs is requested.

Coverity issue: 415049
Fixes: 5e8fcc60b59d ("vhost: enhance virtqueue access lock asserts")

Signed-off-by: David Marchand <david.marchand at redhat.com>
---
 lib/vhost/vhost_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 7fe1687f08..414192500e 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -3171,7 +3171,7 @@ vhost_user_msg_handler(int vid, int fd)
 	 * inactive, so it is safe. Otherwise taking the access_lock
 	 * would cause a dead lock.
 	 */
-	if (msg_handler->lock_all_qps) {
+	if (msg_handler != NULL && msg_handler->lock_all_qps) {
 		if (!(dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) {
 			vhost_user_lock_all_queue_pairs(dev);
 			unlock_required = 1;
-- 
2.44.0