Fix incorrect function signatures in _testmultiphase (UBSan)

[ashm-dev]

Bug report

Bug description:

UBSan reports errors such as:

modexport_create_string

Objects/moduleobject.c:546:13: runtime error: call to function modexport_create_string through pointer to incorrect function type 'struct _object *(*)(struct _object *, struct PyModuleDef *)' /home/shamil/oss/cpython/main/./Modules/_testmultiphase.c:1066:5: note: modexport_create_string defined here SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior Objects/moduleobject.c:546:13

Py_mod_state_free

Objects/moduleobject.c:1101:9: runtime error: call to function modexport_smoke_free through pointer to incorrect function type 'void (*)(void *)' /home/shamil/oss/cpython/main/./Modules/_testmultiphase.c:974: note: modexport_smoke_free defined here SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior Objects/moduleobject.c:1101:9

The functions assigned to Py_mod_state_free and modexport_create_string use incorrect signatures, causing calls through mismatched function pointer types and leading to undefined behavior.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-141553: Fix incorrect function signatures in _testmultiphase #141554

[mohsinm-dev]

@ashm-dev I was working on the same fix.

[ashm-dev]

@mohsinm-dev I already have a fix)

[picnixz]

I am surprised that this was not caught when this was introduced.