Index: Lib/test/pickletester.py
===================================================================
--- Lib/test/pickletester.py	(revision 43495)
+++ Lib/test/pickletester.py	(working copy)
@@ -825,6 +825,24 @@
             y = self.loads(s)
             self.assertEqual(y._proto, None)
 
+    def test_reduce_ex_calls_base(self):
+        for proto in 0, 1, 2:
+            x = REX_four()
+            self.assertEqual(x._proto, None)
+            s = self.dumps(x, proto)
+            self.assertEqual(x._proto, proto)
+            y = self.loads(s)
+            self.assertEqual(y._proto, proto)
+
+    def test_reduce_calls_base(self):
+        for proto in 0, 1, 2:
+            x = REX_five()
+            self.assertEqual(x._reduce_called, 0)
+            s = self.dumps(x, proto)
+            self.assertEqual(x._reduce_called, 1)
+            y = self.loads(s)
+            self.assertEqual(y._reduce_called, 1)
+
 # Test classes for reduce_ex
 
 class REX_one(object):
@@ -849,6 +867,20 @@
     def __reduce__(self):
         raise TestFailed, "This __reduce__ shouldn't be called"
 
+class REX_four(object):
+    _proto = None
+    def __reduce_ex__(self, proto):
+        self._proto = proto
+        return object.__reduce_ex__(self, proto)
+    # Calling base class method should succeed
+
+class REX_five(object):
+    _reduce_called = 0
+    def __reduce__(self):
+        self._reduce_called = 1
+        return object.__reduce__(self)
+    # This one used to fail with infinite recursion
+    
 # Test classes for newobj
 
 class MyInt(int):
Index: Objects/typeobject.c
===================================================================
--- Objects/typeobject.c	(revision 43495)
+++ Objects/typeobject.c	(working copy)
@@ -2773,10 +2773,27 @@
 	return res;
 }
 
+static PyObject *
+object_reduce(PyObject *self, PyObject *args)
+{
+	/* Call copy_reg._reduce_ex(self, 0) */
+	PyObject *copy_reg, *res;
+	int proto = 0;
+
+	copy_reg = import_copy_reg();
+	if (!copy_reg)
+		return NULL;
+
+	res = PyEval_CallMethod(copy_reg, "_reduce_ex", "(Oi)", self, proto);
+	Py_DECREF(copy_reg);
+
+	return res;
+}
+
 static PyMethodDef object_methods[] = {
 	{"__reduce_ex__", object_reduce_ex, METH_VARARGS,
 	 PyDoc_STR("helper for pickle")},
-	{"__reduce__", object_reduce_ex, METH_VARARGS,
+	{"__reduce__", object_reduce, METH_NOARGS,
 	 PyDoc_STR("helper for pickle")},
 	{0}
 };