diff --git a/ChangeLog b/ChangeLog
index a5cae90a53..745f9c9ff1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Mon May 28 12:03:04 2012  Narihiro Nakamura  <authornari@gmail.com>
+
+	* gc.c (obj_free): doesn't free a method table if it doesn't
+	  exits. [ruby-dev:44436]
+	* test/ruby/test_gc.rb (class TestGc): added the test case for
+	  this issue.
+
 Sun May 27 23:37:48 2012  Koichi Sasada  <ko1@atdot.net>
 
 	* benchmark/bm_vm1_lvar_init.rb: added.
diff --git a/gc.c b/gc.c
index 4a96127bf2..92f2e37e17 100644
--- a/gc.c
+++ b/gc.c
@@ -2501,7 +2501,9 @@ obj_free(rb_objspace_t *objspace, VALUE obj)
       case T_MODULE:
       case T_CLASS:
 	rb_clear_cache_by_class((VALUE)obj);
-	rb_free_m_table(RCLASS_M_TBL(obj));
+        if (RCLASS_M_TBL(obj)) {
+            rb_free_m_table(RCLASS_M_TBL(obj));
+        }
 	if (RCLASS_IV_TBL(obj)) {
 	    st_free_table(RCLASS_IV_TBL(obj));
 	}
diff --git a/test/ruby/test_gc.rb b/test/ruby/test_gc.rb
index adcf85e79e..782d8fde3d 100644
--- a/test/ruby/test_gc.rb
+++ b/test/ruby/test_gc.rb
@@ -78,6 +78,20 @@ class TestGc < Test::Unit::TestCase
     EOS
   end
 
+  def test_singleton_method_added
+    assert_in_out_err(%w[--disable-gems], <<-EOS, [], [], "[ruby-dev:44436]")
+      class BasicObject
+        def singleton_method_added(mid)
+          raise
+        end
+      end
+      b = proc {}
+      class << b; end
+      b.clone rescue nil
+      GC.start
+    EOS
+  end
+
   def test_gc_parameter
     env = {
       "RUBY_GC_MALLOC_LIMIT" => "60000000",