diff --git a/ChangeLog b/ChangeLog
index eb6dc638ee..2b2d84f3b9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue Oct 27 16:41:05 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* error.c (rb_error_frozen_object): use rb_attr_get instead of
+	  rb_ivar_get to get rid of warnings for string objects created
+	  when frozen-string-literal-debug is disabled.
+
 Tue Oct 27 16:18:12 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/logger.rb (Logger::Period#previous_period_end): as weekly
diff --git a/error.c b/error.c
index d6fe701fa1..4774ef6a94 100644
--- a/error.c
+++ b/error.c
@@ -2227,8 +2227,12 @@ void
 rb_error_frozen_object(VALUE frozen_obj)
 {
     VALUE path, line;
-    if ((path = rb_iv_get(frozen_obj, "__object_created_path__")) != Qnil &&
-	(line = rb_iv_get(frozen_obj, "__object_created_line__")) != Qnil) {
+    ID created_path, created_line;
+
+    CONST_ID(created_path, "__object_created_path__");
+    CONST_ID(created_line, "__object_created_line__");
+    if (!NIL_P(path = rb_attr_get(frozen_obj, created_path)) &&
+	!NIL_P(line = rb_attr_get(frozen_obj, created_line))) {
 	rb_raise(rb_eRuntimeError, "can't modify frozen %"PRIsVALUE", created at %"PRIsVALUE":%"PRIsVALUE,
 		 CLASS_OF(frozen_obj), path, line);
     }