diff --git a/src/memfile.c b/src/memfile.c
index bd03e65..5412a61 100644
--- a/src/memfile.c
+++ b/src/memfile.c
@@ -234,7 +234,7 @@
 }
 
 /*
- * close a memory file and delete the associated file if 'del_file' is TRUE
+ * Close a memory file and delete the associated file if 'del_file' is TRUE.
  */
     void
 mf_close(mfp, del_file)
@@ -415,7 +415,8 @@
      * Init the data to all zero, to avoid reading uninitialized data.
      * This also avoids that the passwd file ends up in the swap file!
      */
-    (void)vim_memset((char *)(hp->bh_data), 0, (size_t)mfp->mf_page_size);
+    (void)vim_memset((char *)(hp->bh_data), 0,
+				      (size_t)mfp->mf_page_size * page_count);
 
     return hp;
 }