diff --git a/Shorewall/firewall b/Shorewall/firewall
index 2e8966482..e3984afa4 100755
--- a/Shorewall/firewall
+++ b/Shorewall/firewall
@@ -47,7 +47,7 @@ my_mutex_on() {
 }
 
 my_mutex_off() {
-    [ -n "$have_mutex" ] && { mutex_off; HAVE_MUTEX=; }
+    [ -n "$HAVE_MUTEX" ] && { mutex_off; HAVE_MUTEX=; }
 }
 
 #