diff --git a/kernel/marker.c b/kernel/marker.c
index 139260e..b5a9fe1 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -29,7 +29,7 @@
 extern struct marker __stop___markers[];
 
 /* Set to 1 to enable marker debug output */
-const int marker_debug;
+static const int marker_debug;
 
 /*
  * markers_mutex nests inside module_mutex. Markers mutex protects the builtin