diff --git a/src/util.c b/src/util.c
index 2712549..9b8b811 100644
--- a/src/util.c
+++ b/src/util.c
@@ -991,7 +991,7 @@ int expand_workspace_real(const char *func, unsigned int line, unsigned char ***
   if (!(p = whine_realloc_real("expand_workspace", func, line, *wkspc, new * sizeof(unsigned char *))))
     return 0;
 
-  memset(p+old, 0, new-old);
+  memset(p+old, 0, (new-old) * sizeof(unsigned char *));
   
   *wkspc = p;
   *szp = new;