diff --git a/console-server.c b/console-server.c
index 803262b..bcbd4db 100644
--- a/console-server.c
+++ b/console-server.c
@@ -82,7 +82,7 @@
 };
 
 /* size of the shared backlog ringbuffer */
-const size_t buffer_size = 128 * 1024;
+const size_t buffer_size = 128ul * 1024ul;
 
 /* state shared with the signal handler */
 static bool sigint;