diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 609f4f9..561084a 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -403,6 +403,7 @@
 	struct iommu_group *iommu_group = group->iommu_group;
 
 	WARN_ON(!list_empty(&group->device_list));
+	WARN_ON(group->notifier.head);
 
 	list_for_each_entry_safe(unbound, tmp,
 				 &group->unbound_list, unbound_next) {
@@ -1573,6 +1574,10 @@
 		return -EBUSY;
 	}
 
+	/* Warn if previous user didn't cleanup and re-init to drop them */
+	if (WARN_ON(group->notifier.head))
+		BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
+
 	filep->private_data = group;
 
 	return 0;
@@ -1584,9 +1589,6 @@
 
 	filep->private_data = NULL;
 
-	/* Any user didn't unregister? */
-	WARN_ON(group->notifier.head);
-
 	vfio_group_try_dissolve_container(group);
 
 	atomic_dec(&group->opened);