Issue #3740: Null-initialize module state.

Reviewed by Benjamin Peterson.

Misc/NEWS

@@ -15,6 +15,8 @@ What's New in Python 3.0 beta 5
 Core and Builtins
 -----------------
 
+- Issue #3740: Null-initialize module state.
+
 - Issue #3946: PyObject_CheckReadBuffer crashed on a memoryview object.
 
 - Issue #1688: On Windows, the input() prompt was not correctly displayed if it

Objects/moduleobject.c

@@ -113,6 +113,7 @@ PyModule_Create2(struct PyModuleDef* module, int module_api_version)
 			Py_DECREF(m);
 			return NULL;
 		}
+		memset(m->md_state, 0, module->m_size);
 	}
 			
 	d = PyModule_GetDict((PyObject*)m);