diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py index 457b46e01ce317..a29a1a7a523946 100644 --- a/Lib/test/test_exceptions.py +++ b/Lib/test/test_exceptions.py @@ -982,6 +982,21 @@ def g(): self.assertIsInstance(v, RecursionError, type(v)) self.assertIn("maximum recursion depth exceeded", str(v)) + + @cpython_only + def test_crashcan_recursion(self): + # See bpo-33930 + + def foo(): + o = object() + for x in range(1_000_000): + # Create a big chain of method objects that will trigger + # a deep chain of calls when they need to be destructed. + o = o.__dir__ + + foo() + support.gc_collect() + @cpython_only def test_recursion_normalizing_exception(self): # Issue #22898. diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-08-09-14-29-52.bpo-33930.--5LQ-.rst b/Misc/NEWS.d/next/Core and Builtins/2021-08-09-14-29-52.bpo-33930.--5LQ-.rst new file mode 100644 index 00000000000000..827dd3f8b65131 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2021-08-09-14-29-52.bpo-33930.--5LQ-.rst @@ -0,0 +1,2 @@ +Fix segmentation fault with deep recursion when cleaning method objects. +Patch by Augusto Goulart and Pablo Galindo. diff --git a/Objects/methodobject.c b/Objects/methodobject.c index 3604a55e5a1dc9..940de8c326f153 100644 --- a/Objects/methodobject.c +++ b/Objects/methodobject.c @@ -125,7 +125,10 @@ PyCFunction_GetFlags(PyObject *op) static void meth_dealloc(PyCFunctionObject *m) { - _PyObject_GC_UNTRACK(m); + // The Py_TRASHCAN mechanism requires that we be able to + // call PyObject_GC_UnTrack twice on an object. + PyObject_GC_UnTrack(m); + Py_TRASHCAN_BEGIN(m, meth_dealloc); if (m->m_weakreflist != NULL) { PyObject_ClearWeakRefs((PyObject*) m); } @@ -139,6 +142,7 @@ meth_dealloc(PyCFunctionObject *m) else { PyObject_GC_Del(m); } + Py_TRASHCAN_END; } static PyObject *