STINNER Victor <vstin...@python.org> added the comment:
I investigated the FreeIPA crash. * Python 3.8 behaves differently because func_clear() has been implemented (bpo-33418, commit 3c452404ae178b742967589a0bb4a5ec768d76e0) * The bug is a crash on a function call (_PyFunction_Vectorcall) because the function has been cleared (by func_clear), but there was still a weak reference using this function as its callback. * Note: the function is called *during* it's being cleared by func_clear(). * The GC has a workaround for weak references part of "unreachable" objects, but its handle_weakrefs() function doesn't work because CFFI CField_Type type doesn't implement tp_traverse. -- PR 15641 just hides the real bug. One issue is that CFFI doesn't implement correctly the GC protocol. If an object contains another object, its type must: * Have Py_TPFLAGS_HAVE_GC flag * Implement tp_traverse * Use PyObject_GC_Malloc() to allocate an object * Call PyObject_GC_Track() on created object Another issue is that the GC doesn't prevent the crash. Would it be possible to prevent the crash without changing the behavior (ex: still call weakref callbacks)? ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue38006> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
