diff --git a/lib/netdev-notifier-error-inject.c b/lib/netdev-notifier-error-inject.c
index 13e9c62..bb930f2 100644
--- a/lib/netdev-notifier-error-inject.c
+++ b/lib/netdev-notifier-error-inject.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>