https://github.com/python/cpython/commit/3bfc9c831ad9a3dcf4457e842f1e612e93014a17
commit: 3bfc9c831ad9a3dcf4457e842f1e612e93014a17
branch: main
author: Ken Jin <[email protected]>
committer: Fidget-Spinner <[email protected]>
date: 2024-07-11T02:02:08+08:00
summary:
gh-120198: Stop the world when setting __class__ on free-threaded build
(GH-120672)
files:
M Include/internal/pycore_dict.h
M Include/object.h
M Lib/test/test_free_threading/test_type.py
M Objects/dictobject.c
M Objects/typeobject.c
diff --git a/Include/internal/pycore_dict.h b/Include/internal/pycore_dict.h
index 9e0e1237915e82..56cc49432cc61e 100644
--- a/Include/internal/pycore_dict.h
+++ b/Include/internal/pycore_dict.h
@@ -322,6 +322,8 @@ _PyInlineValuesSize(PyTypeObject *tp)
int
_PyDict_DetachFromObject(PyDictObject *dict, PyObject *obj);
+PyDictObject *_PyObject_MaterializeManagedDict_LockHeld(PyObject *);
+
#ifdef __cplusplus
}
#endif
diff --git a/Include/object.h b/Include/object.h
index a1e5b33b0fdaae..abfdb6ce24df21 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -249,11 +249,7 @@ PyAPI_FUNC(PyTypeObject*) Py_TYPE(PyObject *ob);
#else
static inline PyTypeObject* _Py_TYPE(PyObject *ob)
{
- #if defined(Py_GIL_DISABLED)
- return (PyTypeObject *)_Py_atomic_load_ptr_relaxed(&ob->ob_type);
- #else
return ob->ob_type;
- #endif
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
# define Py_TYPE(ob) _Py_TYPE(_PyObject_CAST(ob))
@@ -284,11 +280,7 @@ static inline int Py_IS_TYPE(PyObject *ob, PyTypeObject
*type) {
static inline void Py_SET_TYPE(PyObject *ob, PyTypeObject *type) {
-#ifdef Py_GIL_DISABLED
- _Py_atomic_store_ptr(&ob->ob_type, type);
-#else
ob->ob_type = type;
-#endif
}
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
# define Py_SET_TYPE(ob, type) Py_SET_TYPE(_PyObject_CAST(ob), type)
diff --git a/Lib/test/test_free_threading/test_type.py
b/Lib/test/test_free_threading/test_type.py
index 75259795e81bcb..649676db9c08a5 100644
--- a/Lib/test/test_free_threading/test_type.py
+++ b/Lib/test/test_free_threading/test_type.py
@@ -106,7 +106,7 @@ class Bar:
thing = Foo()
def work():
foo = thing
- for _ in range(10000):
+ for _ in range(5000):
foo.__class__ = Bar
type(foo)
foo.__class__ = Foo
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 2b11a01595b0bc..989c7bb624f488 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -158,6 +158,10 @@ ASSERT_DICT_LOCKED(PyObject *op)
if (!_PyInterpreterState_GET()->stoptheworld.world_stopped) { \
ASSERT_DICT_LOCKED(op); \
}
+#define ASSERT_WORLD_STOPPED_OR_OBJ_LOCKED(op) \
+ if (!_PyInterpreterState_GET()->stoptheworld.world_stopped) { \
+ _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(op); \
+ }
#define IS_DICT_SHARED(mp) _PyObject_GC_IS_SHARED(mp)
#define SET_DICT_SHARED(mp) _PyObject_GC_SET_SHARED(mp)
@@ -227,6 +231,7 @@ static inline void split_keys_entry_added(PyDictKeysObject
*keys)
#define ASSERT_DICT_LOCKED(op)
#define ASSERT_WORLD_STOPPED_OR_DICT_LOCKED(op)
+#define ASSERT_WORLD_STOPPED_OR_OBJ_LOCKED(op)
#define LOCK_KEYS(keys)
#define UNLOCK_KEYS(keys)
#define ASSERT_KEYS_LOCKED(keys)
@@ -6667,10 +6672,10 @@ make_dict_from_instance_attributes(PyInterpreterState
*interp,
return res;
}
-static PyDictObject *
-materialize_managed_dict_lock_held(PyObject *obj)
+PyDictObject *
+_PyObject_MaterializeManagedDict_LockHeld(PyObject *obj)
{
- _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(obj);
+ ASSERT_WORLD_STOPPED_OR_OBJ_LOCKED(obj);
PyDictValues *values = _PyObject_InlineValues(obj);
PyInterpreterState *interp = _PyInterpreterState_GET();
@@ -6699,7 +6704,7 @@ _PyObject_MaterializeManagedDict(PyObject *obj)
goto exit;
}
#endif
- dict = materialize_managed_dict_lock_held(obj);
+ dict = _PyObject_MaterializeManagedDict_LockHeld(obj);
#ifdef Py_GIL_DISABLED
exit:
@@ -7132,7 +7137,7 @@ PyObject_ClearManagedDict(PyObject *obj)
int
_PyDict_DetachFromObject(PyDictObject *mp, PyObject *obj)
{
- _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(obj);
+ ASSERT_WORLD_STOPPED_OR_OBJ_LOCKED(obj);
assert(_PyObject_ManagedDictPointer(obj)->dict == mp);
assert(_PyObject_InlineValuesConsistencyCheck(obj));
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index df895bc65983c0..587632cecfba9d 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -6540,28 +6540,11 @@ compatible_for_assignment(PyTypeObject* oldto,
PyTypeObject* newto, const char*
return 0;
}
-static int
-object_set_class(PyObject *self, PyObject *value, void *closure)
-{
-
- if (value == NULL) {
- PyErr_SetString(PyExc_TypeError,
- "can't delete __class__ attribute");
- return -1;
- }
- if (!PyType_Check(value)) {
- PyErr_Format(PyExc_TypeError,
- "__class__ must be set to a class, not '%s' object",
- Py_TYPE(value)->tp_name);
- return -1;
- }
- PyTypeObject *newto = (PyTypeObject *)value;
- if (PySys_Audit("object.__setattr__", "OsO",
- self, "__class__", value) < 0) {
- return -1;
- }
+static int
+object_set_class_world_stopped(PyObject *self, PyTypeObject *newto)
+{
PyTypeObject *oldto = Py_TYPE(self);
/* In versions of CPython prior to 3.5, the code in
@@ -6627,39 +6610,66 @@ object_set_class(PyObject *self, PyObject *value, void
*closure)
/* Changing the class will change the implicit dict keys,
* so we must materialize the dictionary first. */
if (oldto->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
- PyDictObject *dict = _PyObject_MaterializeManagedDict(self);
+ PyDictObject *dict = _PyObject_GetManagedDict(self);
if (dict == NULL) {
- return -1;
+ dict = _PyObject_MaterializeManagedDict_LockHeld(self);
+ if (dict == NULL) {
+ return -1;
+ }
}
- bool error = false;
-
- Py_BEGIN_CRITICAL_SECTION2(self, dict);
-
- // If we raced after materialization and replaced the dict
- // then the materialized dict should no longer have the
- // inline values in which case detach is a nop.
- assert(_PyObject_GetManagedDict(self) == dict ||
- dict->ma_values != _PyObject_InlineValues(self));
+ assert(_PyObject_GetManagedDict(self) == dict);
if (_PyDict_DetachFromObject(dict, self) < 0) {
- error = true;
- }
-
- Py_END_CRITICAL_SECTION2();
- if (error) {
return -1;
}
+
}
if (newto->tp_flags & Py_TPFLAGS_HEAPTYPE) {
Py_INCREF(newto);
}
- Py_BEGIN_CRITICAL_SECTION(self);
- // The real Py_TYPE(self) (`oldto`) may have changed from
- // underneath us in another thread, so we re-fetch it here.
- oldto = Py_TYPE(self);
+
Py_SET_TYPE(self, newto);
- Py_END_CRITICAL_SECTION();
+
+ return 0;
+ }
+ else {
+ return -1;
+ }
+}
+
+static int
+object_set_class(PyObject *self, PyObject *value, void *closure)
+{
+
+ if (value == NULL) {
+ PyErr_SetString(PyExc_TypeError,
+ "can't delete __class__ attribute");
+ return -1;
+ }
+ if (!PyType_Check(value)) {
+ PyErr_Format(PyExc_TypeError,
+ "__class__ must be set to a class, not '%s' object",
+ Py_TYPE(value)->tp_name);
+ return -1;
+ }
+ PyTypeObject *newto = (PyTypeObject *)value;
+
+ if (PySys_Audit("object.__setattr__", "OsO",
+ self, "__class__", value) < 0) {
+ return -1;
+ }
+
+#ifdef Py_GIL_DISABLED
+ PyInterpreterState *interp = _PyInterpreterState_GET();
+ _PyEval_StopTheWorld(interp);
+#endif
+ PyTypeObject *oldto = Py_TYPE(self);
+ int res = object_set_class_world_stopped(self, newto);
+#ifdef Py_GIL_DISABLED
+ _PyEval_StartTheWorld(interp);
+#endif
+ if (res == 0) {
if (oldto->tp_flags & Py_TPFLAGS_HEAPTYPE) {
Py_DECREF(oldto);
}
@@ -6667,9 +6677,7 @@ object_set_class(PyObject *self, PyObject *value, void
*closure)
RARE_EVENT_INC(set_class);
return 0;
}
- else {
- return -1;
- }
+ return res;
}
static PyGetSetDef object_getsets[] = {
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