bpo-32374: m_traverse may be called with m_state=NULL (GH-5140)
Multi-phase initialized modules allow m_traverse to be called while the
module is still being initialized, so module authors may need to account
for that.
(cherry picked from commit c2b0b12d1a137ada1023ab7c10b8d9a0249d95f9)
Co-authored-by: Marcel Plch <gmarcel.plch@gmail.com>
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index d6cde40..8fb368e 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -21,6 +21,17 @@
{0}
};
+
+/* Helper for sanity check for traverse not handling m_state == NULL
+ * Issue #32374 */
+#ifdef Py_DEBUG
+static int
+bad_traverse_test(PyObject *self, void *arg) {
+ assert(self != NULL);
+ return 0;
+}
+#endif
+
PyTypeObject PyModuleDef_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"moduledef", /* tp_name */
@@ -345,6 +356,16 @@
}
}
+ /* Sanity check for traverse not handling m_state == NULL
+ * This doesn't catch all possible cases, but in many cases it should
+ * make many cases of invalid code crash or raise Valgrind issues
+ * sooner than they would otherwise.
+ * Issue #32374 */
+#ifdef Py_DEBUG
+ if (def->m_traverse != NULL) {
+ def->m_traverse(m, bad_traverse_test, NULL);
+ }
+#endif
Py_DECREF(nameobj);
return m;