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[3.14] gh-129824: fix data races in subinterpreters under TSAN (GH-135794)#136266

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Merged
kumaraditya303 merged 2 commits into from
Jul 6, 2025
Merged

[3.14] gh-129824: fix data races in subinterpreters under TSAN (GH-135794) #136266

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7ee2696
gh-129824: fix data races in subinterpreters under TSAN (GH-135794)
kumaraditya303 Jul 4, 2025
01e844c
Merge branch '3.14' into backport-b582d75-3.14
kumaraditya303 Jul 6, 2025
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61 changes: 44 additions & 17 deletions Objects/typeobject.c
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Original file line numberDiff line numberDiff line change
Expand Up@@ -54,7 +54,6 @@ class object "PyObject *" "&PyBaseObject_Type"
PyUnicode_CheckExact(name) && \
(PyUnicode_GET_LENGTH(name) <= MCACHE_MAX_ATTR_SIZE)

#define NEXT_GLOBAL_VERSION_TAG _PyRuntime.types.next_version_tag
#define NEXT_VERSION_TAG(interp) \
(interp)->types.next_version_tag

Expand DownExpand Up@@ -157,8 +156,8 @@ static_ext_type_lookup(PyInterpreterState *interp, size_t index,
assert(index < _Py_MAX_MANAGED_STATIC_EXT_TYPES);

size_t full_index = index + _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES;
int64_t interp_count =
_PyRuntime.types.managed_static.types[full_index].interp_count;
int64_t interp_count = _Py_atomic_load_int64(
&_PyRuntime.types.managed_static.types[full_index].interp_count);
assert((interp_count == 0) ==
(_PyRuntime.types.managed_static.types[full_index].type == NULL));
*p_interp_count = interp_count;
Expand DownExpand Up@@ -235,7 +234,7 @@ managed_static_type_state_init(PyInterpreterState *interp, PyTypeObject *self,
: index + _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES;

assert((initial == 1) ==
(_PyRuntime.types.managed_static.types[full_index].interp_count == 0));
(_Py_atomic_load_int64(&_PyRuntime.types.managed_static.types[full_index].interp_count) == 0));
(void)_Py_atomic_add_int64(
&_PyRuntime.types.managed_static.types[full_index].interp_count, 1);

Expand DownExpand Up@@ -284,7 +283,7 @@ managed_static_type_state_clear(PyInterpreterState *interp, PyTypeObject *self,
: &(interp->types.for_extensions.initialized[index]);
assert(state != NULL);

assert(_PyRuntime.types.managed_static.types[full_index].interp_count > 0);
assert(_Py_atomic_load_int64(&_PyRuntime.types.managed_static.types[full_index].interp_count) > 0);
assert(_PyRuntime.types.managed_static.types[full_index].type == state->type);

assert(state->type != NULL);
Expand All@@ -294,7 +293,7 @@ managed_static_type_state_clear(PyInterpreterState *interp, PyTypeObject *self,
(void)_Py_atomic_add_int64(
&_PyRuntime.types.managed_static.types[full_index].interp_count, -1);
if (final) {
assert(!_PyRuntime.types.managed_static.types[full_index].interp_count);
assert(!_Py_atomic_load_int64(&_PyRuntime.types.managed_static.types[full_index].interp_count));
_PyRuntime.types.managed_static.types[full_index].type = NULL;

managed_static_type_index_clear(self);
Expand DownExpand Up@@ -1258,6 +1257,19 @@ _PyType_GetVersionForCurrentState(PyTypeObject *tp)
#error "_Py_ATTR_CACHE_UNUSED must be bigger than max"
#endif

static inline unsigned int
next_global_version_tag(void)
{
unsigned int old;
do {
old = _Py_atomic_load_uint_relaxed(&_PyRuntime.types.next_version_tag);
if (old >= _Py_MAX_GLOBAL_TYPE_VERSION_TAG) {
return 0;
}
} while (!_Py_atomic_compare_exchange_uint(&_PyRuntime.types.next_version_tag, &old, old + 1));
return old + 1;
}

static int
assign_version_tag(PyInterpreterState *interp, PyTypeObject *type)
{
Expand DownExpand Up@@ -1288,11 +1300,12 @@ assign_version_tag(PyInterpreterState *interp, PyTypeObject *type)
}
if (type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) {
/* static types */
if (NEXT_GLOBAL_VERSION_TAG > _Py_MAX_GLOBAL_TYPE_VERSION_TAG) {
unsigned int next_version_tag = next_global_version_tag();
if (next_version_tag == 0) {
/* We have run out of version numbers */
return 0;
}
set_version_unlocked(type, NEXT_GLOBAL_VERSION_TAG++);
set_version_unlocked(type, next_version_tag);
assert (type->tp_version_tag <= _Py_MAX_GLOBAL_TYPE_VERSION_TAG);
}
else {
Expand DownExpand Up@@ -8704,7 +8717,11 @@ type_ready_set_new(PyTypeObject *type, int initial)
&& base == &PyBaseObject_Type
&& !(type->tp_flags & Py_TPFLAGS_HEAPTYPE))
{
type_add_flags(type, Py_TPFLAGS_DISALLOW_INSTANTIATION);
if (initial) {
type_add_flags(type, Py_TPFLAGS_DISALLOW_INSTANTIATION);
} else {
assert(type->tp_flags & Py_TPFLAGS_DISALLOW_INSTANTIATION);
}
}

if (!(type->tp_flags & Py_TPFLAGS_DISALLOW_INSTANTIATION)) {
Expand All@@ -8718,13 +8735,17 @@ type_ready_set_new(PyTypeObject *type, int initial)
}
}
else {
// tp_new is NULL: inherit tp_new from base
type->tp_new = base->tp_new;
if (initial) {
// tp_new is NULL: inherit tp_new from base
type->tp_new = base->tp_new;
}
}
}
else {
// Py_TPFLAGS_DISALLOW_INSTANTIATION sets tp_new to NULL
type->tp_new = NULL;
if (initial) {
type->tp_new = NULL;
}
}
return 0;
}
Expand DownExpand Up@@ -8857,7 +8878,12 @@ type_ready(PyTypeObject *type, int initial)
}

/* All done -- set the ready flag */
type_add_flags(type, Py_TPFLAGS_READY);
if (initial) {
type_add_flags(type, Py_TPFLAGS_READY);
} else {
assert(type->tp_flags & Py_TPFLAGS_READY);
}

stop_readying(type);

assert(_PyType_CheckConsistency(type));
Expand DownExpand Up@@ -8906,15 +8932,16 @@ init_static_type(PyInterpreterState *interp, PyTypeObject *self,
assert(!(self->tp_flags & Py_TPFLAGS_MANAGED_DICT));
assert(!(self->tp_flags & Py_TPFLAGS_MANAGED_WEAKREF));

if ((self->tp_flags & Py_TPFLAGS_READY) == 0) {
assert(initial);
if (initial) {
assert((self->tp_flags & Py_TPFLAGS_READY) == 0);

type_add_flags(self, _Py_TPFLAGS_STATIC_BUILTIN);
type_add_flags(self, Py_TPFLAGS_IMMUTABLETYPE);

assert(NEXT_GLOBAL_VERSION_TAG <= _Py_MAX_GLOBAL_TYPE_VERSION_TAG);
if (self->tp_version_tag == 0) {
_PyType_SetVersion(self, NEXT_GLOBAL_VERSION_TAG++);
unsigned int next_version_tag = next_global_version_tag();
assert(next_version_tag != 0);
_PyType_SetVersion(self, next_version_tag);
}
}
else {
Expand Down
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