Index: kern/subr_bus.c
===================================================================
--- kern/subr_bus.c
+++ kern/subr_bus.c
@@ -1949,6 +1949,10 @@
 
 	PDEBUG(("%s from %s", DEVICENAME(child), DEVICENAME(dev)));
 
+	/* detach parent before deleting children, if any */
+	if ((error = device_detach(child)) != 0)
+		return (error);
+	
 	/* remove children first */
 	while ((grandchild = TAILQ_FIRST(&child->children)) != NULL) {
 		error = device_delete_child(child, grandchild);
@@ -1956,8 +1960,6 @@
 			return (error);
 	}
 
-	if ((error = device_detach(child)) != 0)
-		return (error);
 	if (child->devclass)
 		devclass_delete_device(child->devclass, child);
 	if (child->parent)