diff --git a/ChangeLog b/ChangeLog
index 599c992b98..329988c587 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Dec  3 14:34:07 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* string.c (setup_fake_str): fake string does not share another
+	  string, but just should not free.
+
 Wed Dec  3 11:14:14 2014  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/win32.c (w32_spawn): `v2` is used not only for `shell` but also
diff --git a/string.c b/string.c
index 88185cfb0b..95c773bf02 100644
--- a/string.c
+++ b/string.c
@@ -250,7 +250,7 @@ rb_fstring(VALUE str)
 static VALUE
 setup_fake_str(struct RString *fake_str, const char *name, long len, int encidx)
 {
-    fake_str->basic.flags = T_STRING|RSTRING_NOEMBED|ELTS_SHARED;
+    fake_str->basic.flags = T_STRING|RSTRING_NOEMBED|STR_NOFREE;
     /* SHARED to be allocated by the callback */
 
     ENCODING_SET_INLINED((VALUE)fake_str, encidx);