gh-117657: Make Py_TYPE and Py_SET_TYPE thread safe (GH-120165)

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Nadeshiko Manju <me@manjusaka.me>
This commit is contained in:
Ken Jin 2024-06-12 20:41:07 +08:00 committed by GitHub
parent ce3879bd45
commit e16aed63f6
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
5 changed files with 45 additions and 4 deletions

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@ -401,7 +401,10 @@ PyAPI_FUNC(PyStatus) _PyInterpreterState_New(
#define RARE_EVENT_INTERP_INC(interp, name) \
do { \
/* saturating add */ \
if (interp->rare_events.name < UINT8_MAX) interp->rare_events.name++; \
int val = FT_ATOMIC_LOAD_UINT8_RELAXED(interp->rare_events.name); \
if (val < UINT8_MAX) { \
FT_ATOMIC_STORE_UINT8(interp->rare_events.name, val + 1); \
} \
RARE_EVENT_STAT_INC(name); \
} while (0); \

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@ -246,7 +246,11 @@ _Py_IsOwnedByCurrentThread(PyObject *ob)
// bpo-39573: The Py_SET_TYPE() function must be used to set an object type.
static inline PyTypeObject* Py_TYPE(PyObject *ob) {
#ifdef 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))
@ -274,7 +278,11 @@ 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)

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@ -96,6 +96,32 @@ class TestType(TestCase):
self.run_one(writer_func, reader_func)
def test___class___modification(self):
class Foo:
pass
class Bar:
pass
thing = Foo()
def work():
foo = thing
for _ in range(10000):
foo.__class__ = Bar
type(foo)
foo.__class__ = Foo
type(foo)
threads = []
for i in range(NTHREADS):
thread = threading.Thread(target=work)
thread.start()
threads.append(thread)
for thread in threads:
thread.join()
def run_one(self, writer_func, reader_func):
writer = Thread(target=writer_func)
readers = []

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@ -6633,9 +6633,15 @@ object_set_class(PyObject *self, PyObject *value, void *closure)
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);
if (oldto->tp_flags & Py_TPFLAGS_HEAPTYPE)
Py_END_CRITICAL_SECTION();
if (oldto->tp_flags & Py_TPFLAGS_HEAPTYPE) {
Py_DECREF(oldto);
}
RARE_EVENT_INC(set_class);
return 0;

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@ -37,7 +37,6 @@ race_top:set_contains_key
# https://gist.github.com/colesbury/d13d033f413b4ad07929d044bed86c35
race_top:set_discard_entry
race_top:set_inheritable
race_top:Py_SET_TYPE
race_top:_PyDict_CheckConsistency
race_top:_Py_dict_lookup_threadsafe
race_top:_multiprocessing_SemLock_acquire_impl
@ -58,7 +57,6 @@ race_top:_PyFrame_Initialize
race_top:PyInterpreterState_ThreadHead
race_top:_PyObject_TryGetInstanceAttribute
race_top:PyThreadState_Next
race_top:Py_TYPE
race_top:PyUnstable_InterpreterFrame_GetLine
race_top:sock_close
race_top:tstate_delete_common