diff --git a/ChangeLog b/ChangeLog
index 906f1f8581..58e4fcd1d9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Aug 30 22:34:45 2011  CHIKANAGA Tomoyuki  <nagachika00@gmail.com>
+
+	* test/dl/test_callback.rb (test_callback_with_string): prevents
+	  temporary string from GC.
+
 Tue Aug 30 22:25:38 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* vm_insnhelper.c (vm_call_cfunc): revert r33112.  RB_GC_GUARD macro
diff --git a/test/dl/test_callback.rb b/test/dl/test_callback.rb
index ed3be661e7..fb24ff0ca5 100644
--- a/test/dl/test_callback.rb
+++ b/test/dl/test_callback.rb
@@ -48,8 +48,11 @@ module DL
       func = CFunc.new(addr, TYPE_VOID, 'test')
       f = Function.new(func, [TYPE_VOIDP])
 
-      f.call(dlwrap('foo'))
-      assert_equal 'foo', called_with
+      # Don't remove local variable arg.
+      # This necessary to protect objects from GC.
+      arg = 'foo'
+      f.call(dlwrap(arg))
+      assert_equal arg, called_with
     end
 
     def test_call_callback