diff --git a/extras/rule_generator/write_net_rules b/extras/rule_generator/write_net_rules
index b25ecfd8069..9b66c938f39 100644
--- a/extras/rule_generator/write_net_rules
+++ b/extras/rule_generator/write_net_rules
@@ -88,6 +88,7 @@ fi
 
 if [ -z "$match" ]; then
 	echo "missing valid match" >&2
+	unlock_rules_file
 	exit 1
 fi