https://github.com/python/cpython/commit/79688b5b0ea761183193ffb0859415f3b02... commit: 79688b5b0ea761183193ffb0859415f3b02fa44d branch: main author: Sam Gross <colesbury@gmail.com> committer: colesbury <colesbury@gmail.com> date: 2024-04-29T15:49:01-04:00 summary: gh-118331: Handle errors in _PyObject_SetManagedDict (#118334) When detaching a dict, the `copy_values` call may fail due to out-of-memory errors. This can be triggered by test_no_memory in test_repl. files: M Include/cpython/object.h M Objects/dictobject.c M Objects/typeobject.c diff --git a/Include/cpython/object.h b/Include/cpython/object.h index a8f57827a964cd..a6b93b93ab0f7a 100644 --- a/Include/cpython/object.h +++ b/Include/cpython/object.h @@ -493,7 +493,7 @@ do { \ PyAPI_FUNC(void *) PyObject_GetItemData(PyObject *obj); PyAPI_FUNC(int) PyObject_VisitManagedDict(PyObject *obj, visitproc visit, void *arg); -PyAPI_FUNC(void) _PyObject_SetManagedDict(PyObject *obj, PyObject *new_dict); +PyAPI_FUNC(int) _PyObject_SetManagedDict(PyObject *obj, PyObject *new_dict); PyAPI_FUNC(void) PyObject_ClearManagedDict(PyObject *obj); #define TYPE_MAX_WATCHERS 8 diff --git a/Objects/dictobject.c b/Objects/dictobject.c index 43cb2350b7fc71..1f21f70f149c80 100644 --- a/Objects/dictobject.c +++ b/Objects/dictobject.c @@ -7056,11 +7056,12 @@ set_dict_inline_values(PyObject *obj, PyDictObject *new_dict) } } -void +int _PyObject_SetManagedDict(PyObject *obj, PyObject *new_dict) { assert(Py_TYPE(obj)->tp_flags & Py_TPFLAGS_MANAGED_DICT); assert(_PyObject_InlineValuesConsistencyCheck(obj)); + int err = 0; PyTypeObject *tp = Py_TYPE(obj); if (tp->tp_flags & Py_TPFLAGS_INLINE_VALUES) { PyDictObject *dict = _PyObject_GetManagedDict(obj); @@ -7076,11 +7077,11 @@ _PyObject_SetManagedDict(PyObject *obj, PyObject *new_dict) Py_END_CRITICAL_SECTION(); if (dict == NULL) { - return; + return 0; } #else set_dict_inline_values(obj, (PyDictObject *)new_dict); - return; + return 0; #endif } @@ -7089,15 +7090,16 @@ _PyObject_SetManagedDict(PyObject *obj, PyObject *new_dict) // We've locked dict, but the actual dict could have changed // since we locked it. dict = _PyObject_ManagedDictPointer(obj)->dict; - - FT_ATOMIC_STORE_PTR(_PyObject_ManagedDictPointer(obj)->dict, - (PyDictObject *)Py_XNewRef(new_dict)); - - _PyDict_DetachFromObject(dict, obj); - + err = _PyDict_DetachFromObject(dict, obj); + if (err == 0) { + FT_ATOMIC_STORE_PTR(_PyObject_ManagedDictPointer(obj)->dict, + (PyDictObject *)Py_XNewRef(new_dict)); + } Py_END_CRITICAL_SECTION2(); - Py_XDECREF(dict); + if (err == 0) { + Py_XDECREF(dict); + } } else { PyDictObject *dict; @@ -7114,18 +7116,23 @@ _PyObject_SetManagedDict(PyObject *obj, PyObject *new_dict) Py_XDECREF(dict); } assert(_PyObject_InlineValuesConsistencyCheck(obj)); + return err; } void PyObject_ClearManagedDict(PyObject *obj) { - _PyObject_SetManagedDict(obj, NULL); + if (_PyObject_SetManagedDict(obj, NULL) < 0) { + PyErr_WriteUnraisable(NULL); + } } int _PyDict_DetachFromObject(PyDictObject *mp, PyObject *obj) { _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(obj); + assert(_PyObject_ManagedDictPointer(obj)->dict == mp); + assert(_PyObject_InlineValuesConsistencyCheck(obj)); if (FT_ATOMIC_LOAD_PTR_RELAXED(mp->ma_values) != _PyObject_InlineValues(obj)) { return 0; diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 07e0a5a02da87f..50efbb6e182df0 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -3167,7 +3167,7 @@ subtype_setdict(PyObject *obj, PyObject *value, void *context) } if (Py_TYPE(obj)->tp_flags & Py_TPFLAGS_MANAGED_DICT) { - _PyObject_SetManagedDict(obj, value); + return _PyObject_SetManagedDict(obj, value); } else { dictptr = _PyObject_ComputedDictPointer(obj);