diff --git a/ChangeLog b/ChangeLog
index d69317e3a9..8b720c3d13 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Nov 22 00:44:59 2011  Tanaka Akira  <akr@fsij.org>
+
+	* test/ruby/test_io.rb (test_fcntl_dupfd): the argument of F_DUPFD is
+	  minimum file descriptor.
+
 Tue Nov 22 00:25:17 2011  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (linux_get_maxfd): get rid of a warning.
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 35b29068b9..7623053c79 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1922,7 +1922,7 @@ End
     Tempfile.open(self.class.name) do |f|
       fd = f.fcntl(Fcntl::F_DUPFD, 63)
       begin
-        assert_equal(fd, 63)
+        assert_operator(fd, :>=, 63)
       ensure
         IO.for_fd(fd).close
       end