From f0d290d25cad66e615ada68ba190b8a23ac1deaa Mon Sep 17 00:00:00 2001 From: Pablo Galindo Salgado Date: Thu, 9 Dec 2021 13:53:44 +0000 Subject: bpo-46025: Fix a crash in the atexit module for auto-unregistering functions (GH-30002) --- Lib/test/_test_atexit.py | 15 +++++++++++++++ .../2021-12-09-11-41-35.bpo-46025.pkEvW9.rst | 2 ++ Modules/atexitmodule.c | 5 ++++- 3 files changed, 21 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2021-12-09-11-41-35.bpo-46025.pkEvW9.rst diff --git a/Lib/test/_test_atexit.py b/Lib/test/_test_atexit.py index a316585..55d2808 100644 --- a/Lib/test/_test_atexit.py +++ b/Lib/test/_test_atexit.py @@ -116,6 +116,21 @@ class GeneralTest(unittest.TestCase): atexit._run_exitfuncs() self.assertEqual(l, [5]) + def test_atexit_with_unregistered_function(self): + # See bpo-46025 for more info + def func(): + atexit.unregister(func) + 1/0 + atexit.register(func) + try: + with support.catch_unraisable_exception() as cm: + atexit._run_exitfuncs() + self.assertEqual(cm.unraisable.object, func) + self.assertEqual(cm.unraisable.exc_type, ZeroDivisionError) + self.assertEqual(type(cm.unraisable.exc_value), ZeroDivisionError) + finally: + atexit.unregister(func) + if __name__ == "__main__": unittest.main() diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-12-09-11-41-35.bpo-46025.pkEvW9.rst b/Misc/NEWS.d/next/Core and Builtins/2021-12-09-11-41-35.bpo-46025.pkEvW9.rst new file mode 100644 index 0000000..dd2f1ff --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2021-12-09-11-41-35.bpo-46025.pkEvW9.rst @@ -0,0 +1,2 @@ +Fix a crash in the :mod:`atexit` module involving functions that unregister +themselves before raising exceptions. Patch by Pablo Galindo. diff --git a/Modules/atexitmodule.c b/Modules/atexitmodule.c index e536b4a..95c653c 100644 --- a/Modules/atexitmodule.c +++ b/Modules/atexitmodule.c @@ -93,13 +93,16 @@ atexit_callfuncs(struct atexit_state *state) continue; } + // bpo-46025: Increment the refcount of cb->func as the call itself may unregister it + PyObject* the_func = Py_NewRef(cb->func); PyObject *res = PyObject_Call(cb->func, cb->args, cb->kwargs); if (res == NULL) { - _PyErr_WriteUnraisableMsg("in atexit callback", cb->func); + _PyErr_WriteUnraisableMsg("in atexit callback", the_func); } else { Py_DECREF(res); } + Py_DECREF(the_func); } atexit_cleanup(state); -- cgit v0.12