diff --git a/ChangeLog b/ChangeLog
index fbe0862f07..6c84799da0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Mar 29 22:09:46 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* thread.c (rb_mutex_synchronize_m): yield no block params.  patch by
+	  splattael (Peter Suschlik) in [ruby-core:53773] [Bug #8097].
+	  fix GH-266.
+
 Fri Mar 29 16:51:39 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* io.c (argf_next_argv): set init flag if succeeded to forward, after
diff --git a/test/ruby/test_thread.rb b/test/ruby/test_thread.rb
index 63921bb2da..668f3741e3 100644
--- a/test/ruby/test_thread.rb
+++ b/test/ruby/test_thread.rb
@@ -120,6 +120,11 @@ class TestThread < Test::Unit::TestCase
     assert_equal(max * max * max, r)
   end
 
+  def test_mutex_synchronize_yields_no_block_params
+    bug8097 = '[ruby-core:53424] [Bug #8097]'
+    assert_empty(Mutex.new.synchronize {|*params| break params}, bug8097)
+  end
+
   def test_local_barrier
     dir = File.dirname(__FILE__)
     lbtest = File.join(dir, "lbtest.rb")
diff --git a/thread.c b/thread.c
index c510b93e9a..5312648a57 100644
--- a/thread.c
+++ b/thread.c
@@ -4567,7 +4567,7 @@ rb_mutex_synchronize_m(VALUE self, VALUE args)
 	rb_raise(rb_eThreadError, "must be called with a block");
     }
 
-    return rb_mutex_synchronize(self, rb_yield, Qnil);
+    return rb_mutex_synchronize(self, rb_yield, Qundef);
 }
 
 void rb_mutex_allow_trap(VALUE self, int val)