diff -r 03739fa3fc5c pypy/module/cpyext/pyobject.py
--- a/pypy/module/cpyext/pyobject.py	Tue Apr 03 06:06:40 2018 +0300
+++ b/pypy/module/cpyext/pyobject.py	Tue Apr 03 07:51:49 2018 +0200
@@ -60,7 +60,7 @@
 
     def _cpyext_attach_pyobj(self, space, py_obj):
         self._cpy_ref = py_obj
-        rawrefcount.create_link_pyobj(self, py_obj)
+        rawrefcount.create_link_pypy(self, py_obj)
     cls._cpyext_attach_pyobj = _cpyext_attach_pyobj
 
 add_direct_pyobj_storage(W_BaseCPyObject)
diff -r 03739fa3fc5c pypy/module/cpyext/typeobject.py
--- a/pypy/module/cpyext/typeobject.py	Tue Apr 03 06:06:40 2018 +0300
+++ b/pypy/module/cpyext/typeobject.py	Tue Apr 03 07:51:49 2018 +0200
@@ -517,6 +517,10 @@
             self.w_doc = space.newtext(
                 rffi.charp2str(cts.cast('char*', pto.c_tp_doc)))
 
+    def _cpyext_attach_pyobj(self, space, py_obj):
+        self._cpy_ref = py_obj
+        rawrefcount.create_link_pyobj(self, py_obj)
+
 @bootstrap_function
 def init_typeobject(space):
     make_typedescr(space.w_type.layout.typedef,