diff --git a/ChangeLog b/ChangeLog
index 4615677138..04ab432a0f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Jun 17 12:24:57 2014  Koichi Sasada  <ko1@atdot.net>
+
+	* gc.c (obj_memsize_of): memsize_of(T_ZOMBIE) returns 0, not a rb_bug.
+	  ObjectSpace.count_objects_size() uses memsize_of(T_ZOMBIE).
+
+	  This bug introduced at r46348.
+
 Mon Jun 16 19:00:11 2014  Koichi Sasada  <ko1@atdot.net>
 
 	* test/runner.rb: failure message should be passed as an argument.
diff --git a/gc.c b/gc.c
index ba70b33cc1..8ab7fbfa20 100644
--- a/gc.c
+++ b/gc.c
@@ -2610,7 +2610,7 @@ obj_memsize_of(VALUE obj, int use_tdata)
 	break;
 
       case T_ZOMBIE:
-	/* fall through */
+	break;
 
       default:
 	rb_bug("objspace/memsize_of(): unknown data type 0x%x(%p)",