diff --git a/ChangeLog b/ChangeLog
index 3519748307..0431c120b3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Dec 22 14:17:02 2007  Koichi Sasada  <ko1@atdot.net>
+
+	* bootstraptest/test_objectspace.rb: skip flozen string.
+
 Sat Dec 22 14:02:58 2007  Koichi Sasada  <ko1@atdot.net>
 
 	* array.c (rb_ary_permutation): add volatile to avoid GC problem.
diff --git a/bootstraptest/test_objectspace.rb b/bootstraptest/test_objectspace.rb
index 4f93341f72..ca738f5d63 100644
--- a/bootstraptest/test_objectspace.rb
+++ b/bootstraptest/test_objectspace.rb
@@ -17,7 +17,7 @@ assert_normal_exit %q{
   ary.permutation(2) {|x|
     if x == [1,2]
       ObjectSpace.each_object(String) {|s|
-        s.clear if s.length == 40 || s.length == 80
+        s.clear if s.frozen? && (s.length == 40 || s.length == 80)
       }
     end
   }