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gh-117657: Fix data races reported by TSAN in some set methods (#120914)

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Refactor the fast Unicode hash check into `_PyObject_HashFast` and use relaxed
atomic loads in the free-threaded build.

After this change, the TSAN doesn't report data races for this method.
This commit is contained in:
AN Long 2024-07-02 03:11:39 +08:00 committed by GitHub
parent 9bcb7d8c6f
commit 294e724964
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GPG Key ID: B5690EEEBB952194
6 changed files with 81 additions and 121 deletions
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14
Include/internal/pycore_object.h
View File

@ -613,6 +613,20 @@ _PyObject_IS_GC(PyObject *obj)
&& (type->tp_is_gc == NULL || type->tp_is_gc(obj)));
}
// Fast inlined version of PyObject_Hash()
static inline Py_hash_t
_PyObject_HashFast(PyObject *op)
{
if (PyUnicode_CheckExact(op)) {
Py_hash_t hash = FT_ATOMIC_LOAD_SSIZE_RELAXED(
_PyASCIIObject_CAST(op)->hash);
if (hash != -1) {
return hash;
}
}
return PyObject_Hash(op);
}
// Fast inlined version of PyType_IS_GC()
#define _PyType_IS_GC(t) _PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)

9
Modules/_collectionsmodule.c
View File

@ -2537,12 +2537,9 @@ _collections__count_elements_impl(PyObject *module, PyObject *mapping,
if (key == NULL)
break;
if (!PyUnicode_CheckExact(key) ||
(hash = _PyASCIIObject_CAST(key)->hash) == -1)
{
hash = PyObject_Hash(key);
if (hash == -1)
goto done;
hash = _PyObject_HashFast(key);
if (hash == -1) {
goto done;
}
oldval = _PyDict_GetItem_KnownHash(mapping, key, hash);

135
Objects/dictobject.c
View File

@ -433,7 +433,7 @@ static inline Py_hash_t
unicode_get_hash(PyObject *o)
{
assert(PyUnicode_CheckExact(o));
return _PyASCIIObject_CAST(o)->hash;
return FT_ATOMIC_LOAD_SSIZE_RELAXED(_PyASCIIObject_CAST(o)->hash);
}
/* Print summary info about the state of the optimized allocator */
@ -2177,13 +2177,10 @@ dict_getitem(PyObject *op, PyObject *key, const char *warnmsg)
}
PyDictObject *mp = (PyDictObject *)op;
Py_hash_t hash;
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1) {
PyErr_FormatUnraisable(warnmsg);
return NULL;
}
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
PyErr_FormatUnraisable(warnmsg);
return NULL;
}
PyThreadState *tstate = _PyThreadState_GET();
@ -2232,12 +2229,9 @@ _PyDict_LookupIndex(PyDictObject *mp, PyObject *key)
assert(PyDict_CheckExact((PyObject*)mp));
assert(PyUnicode_CheckExact(key));
Py_hash_t hash = unicode_get_hash(key);
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
hash = PyObject_Hash(key);
if (hash == -1) {
return -1;
}
return -1;
}
return _Py_dict_lookup(mp, key, hash, &value);
@ -2308,14 +2302,10 @@ PyDict_GetItemRef(PyObject *op, PyObject *key, PyObject **result)
return -1;
}
Py_hash_t hash;
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1)
{
hash = PyObject_Hash(key);
if (hash == -1) {
*result = NULL;
return -1;
}
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
*result = NULL;
return -1;
}
return _PyDict_GetItemRef_KnownHash((PyDictObject *)op, key, hash, result);
@ -2327,13 +2317,10 @@ _PyDict_GetItemRef_Unicode_LockHeld(PyDictObject *op, PyObject *key, PyObject **
ASSERT_DICT_LOCKED(op);
assert(PyUnicode_CheckExact(key));
Py_hash_t hash;
if ((hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1) {
*result = NULL;
return -1;
}
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
*result = NULL;
return -1;
}
PyObject *value;
@ -2367,12 +2354,9 @@ PyDict_GetItemWithError(PyObject *op, PyObject *key)
PyErr_BadInternalCall();
return NULL;
}
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1)
{
hash = PyObject_Hash(key);
if (hash == -1) {
return NULL;
}
hash = _PyObject_HashFast(key);
if (hash == -1) {
return NULL;
}
#ifdef Py_GIL_DISABLED
@ -2440,10 +2424,9 @@ _PyDict_LoadGlobal(PyDictObject *globals, PyDictObject *builtins, PyObject *key)
Py_hash_t hash;
PyObject *value;
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return NULL;
hash = _PyObject_HashFast(key);
if (hash == -1) {
return NULL;
}
/* namespace 1: globals */
@ -2468,14 +2451,11 @@ setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
assert(key);
assert(value);
assert(PyDict_Check(mp));
Py_hash_t hash;
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1) {
Py_DECREF(key);
Py_DECREF(value);
return -1;
}
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
Py_DECREF(key);
Py_DECREF(value);
return -1;
}
PyInterpreterState *interp = _PyInterpreterState_GET();
@ -2624,12 +2604,10 @@ delitem_common(PyDictObject *mp, Py_hash_t hash, Py_ssize_t ix,
int
PyDict_DelItem(PyObject *op, PyObject *key)
{
Py_hash_t hash;
assert(key);
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return -1;
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
return -1;
}
return _PyDict_DelItem_KnownHash(op, key, hash);
@ -2953,15 +2931,12 @@ pop_lock_held(PyObject *op, PyObject *key, PyObject **result)
return 0;
}
Py_hash_t hash;
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1) {
if (result) {
*result = NULL;
}
return -1;
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
if (result) {
*result = NULL;
}
return -1;
}
return _PyDict_Pop_KnownHash(dict, key, hash, result);
}
@ -3293,10 +3268,9 @@ dict_subscript(PyObject *self, PyObject *key)
Py_hash_t hash;
PyObject *value;
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return NULL;
hash = _PyObject_HashFast(key);
if (hash == -1) {
return NULL;
}
ix = _Py_dict_lookup_threadsafe(mp, key, hash, &value);
if (ix == DKIX_ERROR)
@ -4183,10 +4157,9 @@ dict_get_impl(PyDictObject *self, PyObject *key, PyObject *default_value)
Py_hash_t hash;
Py_ssize_t ix;
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return NULL;
hash = _PyObject_HashFast(key);
if (hash == -1) {
return NULL;
}
ix = _Py_dict_lookup_threadsafe(self, key, hash, &val);
if (ix == DKIX_ERROR)
@ -4216,14 +4189,12 @@ dict_setdefault_ref_lock_held(PyObject *d, PyObject *key, PyObject *default_valu
return -1;
}
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1) {
if (result) {
*result = NULL;
}
return -1;
hash = _PyObject_HashFast(key);
if (hash == -1) {
if (result) {
*result = NULL;
}
return -1;
}
if (mp->ma_keys == Py_EMPTY_KEYS) {
@ -4655,12 +4626,10 @@ static PyMethodDef mapp_methods[] = {
int
PyDict_Contains(PyObject *op, PyObject *key)
{
Py_hash_t hash;
Py_hash_t hash = _PyObject_HashFast(key);
if (!PyUnicode_CheckExact(key) || (hash = unicode_get_hash(key)) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return -1;
if (hash == -1) {
return -1;
}
return _PyDict_Contains_KnownHash(op, key, hash);
@ -6743,11 +6712,9 @@ int
_PyDict_SetItem_LockHeld(PyDictObject *dict, PyObject *name, PyObject *value)
{
if (value == NULL) {
Py_hash_t hash;
if (!PyUnicode_CheckExact(name) || (hash = unicode_get_hash(name)) == -1) {
hash = PyObject_Hash(name);
if (hash == -1)
return -1;
Py_hash_t hash = _PyObject_HashFast(name);
if (hash == -1) {
return -1;
}
return delitem_knownhash_lock_held((PyObject *)dict, name, hash);
} else {

30
Objects/setobject.c
View File

@ -365,13 +365,9 @@ set_discard_entry(PySetObject *so, PyObject *key, Py_hash_t hash)
static int
set_add_key(PySetObject *so, PyObject *key)
{
Py_hash_t hash;
if (!PyUnicode_CheckExact(key) ||
(hash = _PyASCIIObject_CAST(key)->hash) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return -1;
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
return -1;
}
return set_add_entry(so, key, hash);
}
@ -379,13 +375,9 @@ set_add_key(PySetObject *so, PyObject *key)
static int
set_contains_key(PySetObject *so, PyObject *key)
{
Py_hash_t hash;
if (!PyUnicode_CheckExact(key) ||
(hash = _PyASCIIObject_CAST(key)->hash) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return -1;
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
return -1;
}
return set_contains_entry(so, key, hash);
}
@ -393,13 +385,9 @@ set_contains_key(PySetObject *so, PyObject *key)
static int
set_discard_key(PySetObject *so, PyObject *key)
{
Py_hash_t hash;
if (!PyUnicode_CheckExact(key) ||
(hash = _PyASCIIObject_CAST(key)->hash) == -1) {
hash = PyObject_Hash(key);
if (hash == -1)
return -1;
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
return -1;
}
return set_discard_entry(so, key, hash);
}

13
Objects/typeobject.c
View File

@ -5251,15 +5251,10 @@ find_name_in_mro(PyTypeObject *type, PyObject *name, int *error)
{
ASSERT_TYPE_LOCK_HELD();
Py_hash_t hash;
if (!PyUnicode_CheckExact(name) ||
(hash = _PyASCIIObject_CAST(name)->hash) == -1)
{
hash = PyObject_Hash(name);
if (hash == -1) {
*error = -1;
return NULL;
}
Py_hash_t hash = _PyObject_HashFast(name);
if (hash == -1) {
*error = -1;
return NULL;
}
/* Look in tp_dict of types in MRO */

1
Tools/tsan/suppressions_free_threading.txt
View File

@ -30,7 +30,6 @@ race_top:assign_version_tag
race_top:insertdict
race_top:lookup_tp_dict
race_top:new_reference
race_top:set_contains_key
# https://gist.github.com/colesbury/d13d033f413b4ad07929d044bed86c35
race_top:set_discard_entry
race_top:_PyDict_CheckConsistency