[issue38006] Crash in remove() weak reference callback of weakref.WeakValueDictionary at Python exit

[STINNER Victor]

STINNER Victor <vstinner at python.org> added the comment:

I'm now able to reproduce the FreeIPA crash. In short:

* Get a Fedora Rawhide VM (to get Python 3.8 as "python3", it's more convenient)
* Install FreeIPA (dnf install freeipa-server)
* Run: ipa-server-install --help
* Python does crash at exit


> In particular, this was not happening before because the function type did not implement tp_clear:
> https://github.com/python/cpython/blob/3.7/Objects/funcobject.c#L615

I confirm that the patch below does fix the FreeIPA crash:

diff --git a/Objects/funcobject.c b/Objects/funcobject.c
index df5cc2d3f5..357372c565 100644
--- a/Objects/funcobject.c
+++ b/Objects/funcobject.c
@@ -669,7 +669,7 @@ PyTypeObject PyFunction_Type = {
     Py_TPFLAGS_METHOD_DESCRIPTOR,               /* tp_flags */
     func_new__doc__,                            /* tp_doc */
     (traverseproc)func_traverse,                /* tp_traverse */
-    (inquiry)func_clear,                        /* tp_clear */
+    (inquiry)0,                        /* tp_clear */
     0,                                          /* tp_richcompare */
     offsetof(PyFunctionObject, func_weakreflist), /* tp_weaklistoffset */
     0,                                          /* tp_iter */

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38006>
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