diff --git a/ChangeLog b/ChangeLog
index f9165021c0..6ab9da7574 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Dec 26 14:25:03 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* hash.c (HASH_REJECT_COPY_EXTRA_STATES): turn off the old
+	  behavior, copying extra states by accident.
+
 Thu Dec 26 10:49:14 2013  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* version.h (RUBY_VERSION): 2.2.0 development has started.
diff --git a/hash.c b/hash.c
index db70939505..004ee920e3 100644
--- a/hash.c
+++ b/hash.c
@@ -31,7 +31,7 @@
     ((klass = has_extra_methods(rb_obj_class(hash))) != 0) || \
     FL_TEST((hash), FL_EXIVAR|FL_TAINT|HASH_PROC_DEFAULT) || \
     !NIL_P(RHASH_IFNONE(hash)))
-#define HASH_REJECT_COPY_EXTRA_STATES 1
+#define HASH_REJECT_COPY_EXTRA_STATES 0
 
 static VALUE
 has_extra_methods(VALUE klass)