https://github.com/python/cpython/commit/3ea7276a8e9edcf5cc5409448467023a34d4f083
commit: 3ea7276a8e9edcf5cc5409448467023a34d4f083
branch: 3.14
author: Miss Islington (bot) <31488909+miss-isling...@users.noreply.github.com>
committer: kumaraditya303 <kumaradi...@python.org>
date: 2025-07-06T18:53:55+05:30
summary:
[3.14] gh-129824: fix data races in subinterpreters under TSAN (GH-135794)
(#136266)
gh-129824: fix data races in subinterpreters under TSAN (GH-135794)
This fixes the data races in typeobject.c in subinterpreters under
free-threading. The type flags and slots are only modified in the main
interpreter as all static types are first initialised in main interpreter.
(cherry picked from commit b582d751b4968d4534fdb7894e50713676789b2f)
Co-authored-by: Kumar Aditya <kumaradi...@python.org>
files:
M Objects/typeobject.c
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 455d32434c4688..a348ea1d531c93 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -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
@@ -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;
@@ -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);
@@ -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);
@@ -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);
@@ -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)
{
@@ -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 {
@@ -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)) {
@@ -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;
}
@@ -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));
@@ -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 {
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