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[gh-117657] Fix some issues with TSAN in typeobject (#118249)

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Fix some racing reads in typebobject.c
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Dino Viehland 2024-04-30 12:37:38 -07:00 • committed by GitHub
parent b2c3b70c71
commit 19d468a3ab
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GPG key ID: B5690EEEBB952194
2 changed files with 19 additions and 6 deletions
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17
Objects/typeobject.c
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@ -43,7 +43,8 @@ class object "PyObject *" "&PyBaseObject_Type"
& ((1 << MCACHE_SIZE_EXP) - 1))
#define MCACHE_HASH_METHOD(type, name) \
MCACHE_HASH((type)->tp_version_tag, ((Py_ssize_t)(name)) >> 3)
MCACHE_HASH(FT_ATOMIC_LOAD_UINT32_RELAXED((type)->tp_version_tag), \
((Py_ssize_t)(name)) >> 3)
#define MCACHE_CACHEABLE_NAME(name) \
PyUnicode_CheckExact(name) && \
PyUnicode_IS_READY(name) && \
@ -907,7 +908,7 @@ type_modified_unlocked(PyTypeObject *type)
}
type->tp_flags &= ~Py_TPFLAGS_VALID_VERSION_TAG;
type->tp_version_tag = 0; /* 0 is not a valid version tag */
FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag, 0); /* 0 is not a valid version tag */
if (PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
// This field *must* be invalidated if the type is modified (see the
// comment on struct _specialization_cache):
@ -984,7 +985,7 @@ type_mro_modified(PyTypeObject *type, PyObject *bases) {
clear:
assert(!(type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN));
type->tp_flags &= ~Py_TPFLAGS_VALID_VERSION_TAG;
type->tp_version_tag = 0; /* 0 is not a valid version tag */
FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag, 0); /* 0 is not a valid version tag */
if (PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
// This field *must* be invalidated if the type is modified (see the
// comment on struct _specialization_cache):
@ -1020,7 +1021,8 @@ assign_version_tag(PyInterpreterState *interp, PyTypeObject *type)
/* We have run out of version numbers */
return 0;
}
type->tp_version_tag = NEXT_GLOBAL_VERSION_TAG++;
FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag,
NEXT_GLOBAL_VERSION_TAG++);
assert (type->tp_version_tag <= _Py_MAX_GLOBAL_TYPE_VERSION_TAG);
}
else {
@ -1029,7 +1031,8 @@ assign_version_tag(PyInterpreterState *interp, PyTypeObject *type)
/* We have run out of version numbers */
return 0;
}
type->tp_version_tag = NEXT_VERSION_TAG(interp)++;
FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag,
NEXT_VERSION_TAG(interp)++);
assert (type->tp_version_tag != 0);
}
@ -5085,7 +5088,9 @@ _PyType_Lookup(PyTypeObject *type, PyObject *name)
// synchronize-with other writing threads by doing an acquire load on the sequence
while (1) {
int sequence = _PySeqLock_BeginRead(&entry->sequence);
if (_Py_atomic_load_uint32_relaxed(&entry->version) == type->tp_version_tag &&
uint32_t entry_version = _Py_atomic_load_uint32_relaxed(&entry->version);
uint32_t type_version = _Py_atomic_load_uint32_relaxed(&type->tp_version_tag);
if (entry_version == type_version &&
_Py_atomic_load_ptr_relaxed(&entry->name) == name) {
assert(_PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG));
OBJECT_STAT_INC_COND(type_cache_hits, !is_dunder_name(name));