diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 99dc592..4ddb38b 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -1193,13 +1193,15 @@
 
 void subsys_interface_unregister(struct subsys_interface *sif)
 {
-	struct bus_type *subsys = sif->subsys;
+	struct bus_type *subsys;
 	struct subsys_dev_iter iter;
 	struct device *dev;
 
-	if (!sif)
+	if (!sif || !sif->subsys)
 		return;
 
+	subsys = sif->subsys;
+
 	mutex_lock(&subsys->p->mutex);
 	list_del_init(&sif->node);
 	if (sif->remove_dev) {