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gh-130312: SET_ADD should not lock (#130136)

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SET_ADD should not lock
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Dino Viehland 2025-03-21 15:58:32 -07:00 • committed by GitHub
parent 7101cba6bf
commit d9411ae3c2
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GPG key ID: B5690EEEBB952194
5 changed files with 76 additions and 59 deletions
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2
Include/internal/pycore_setobject.h
View file

@ -33,6 +33,8 @@ PyAPI_FUNC(int) _PySet_Contains(PySetObject *so, PyObject *key);
// Clears the set without acquiring locks. Used by _PyCode_Fini.
extern void _PySet_ClearInternal(PySetObject *so);
PyAPI_FUNC(int) _PySet_AddTakeRef(PySetObject *so, PyObject *key);
#ifdef __cplusplus
}
#endif

29
Objects/setobject.c
View file

@ -122,7 +122,7 @@ set_lookkey(PySetObject *so, PyObject *key, Py_hash_t hash)
static int set_table_resize(PySetObject *, Py_ssize_t);
static int
set_add_entry(PySetObject *so, PyObject *key, Py_hash_t hash)
set_add_entry_takeref(PySetObject *so, PyObject *key, Py_hash_t hash)
{
setentry *table;
setentry *freeslot;
@ -133,12 +133,6 @@ set_add_entry(PySetObject *so, PyObject *key, Py_hash_t hash)
int probes;
int cmp;
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(so);
/* Pre-increment is necessary to prevent arbitrary code in the rich
comparison from deallocating the key just before the insertion. */
Py_INCREF(key);
restart:
mask = so->mask;
@ -209,6 +203,27 @@ set_add_entry(PySetObject *so, PyObject *key, Py_hash_t hash)
return -1;
}
static int
set_add_entry(PySetObject *so, PyObject *key, Py_hash_t hash)
{
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(so);
return set_add_entry_takeref(so, Py_NewRef(key), hash);
}
int
_PySet_AddTakeRef(PySetObject *so, PyObject *key)
{
Py_hash_t hash = _PyObject_HashFast(key);
if (hash == -1) {
Py_DECREF(key);
return -1;
}
// We don't pre-increment here, the caller holds a strong
// reference to the object which we are stealing.
return set_add_entry_takeref(so, key, hash);
}
/*
Internal routine used by set_table_resize() to insert an item which is
known to be absent from the set. Besides the performance benefit,

20
Python/bytecodes.c
View file

@ -975,9 +975,8 @@ dummy_func(
}
inst(SET_ADD, (set, unused[oparg-1], v -- set, unused[oparg-1])) {
int err = PySet_Add(PyStackRef_AsPyObjectBorrow(set),
PyStackRef_AsPyObjectBorrow(v));
PyStackRef_CLOSE(v);
int err = _PySet_AddTakeRef((PySetObject *)PyStackRef_AsPyObjectBorrow(set),
PyStackRef_AsPyObjectSteal(v));
ERROR_IF(err, error);
}
@ -1916,17 +1915,24 @@ dummy_func(
DECREF_INPUTS();
ERROR_IF(true, error);
}
int err = 0;
for (int i = 0; i < oparg; i++) {
for (Py_ssize_t i = 0; i < oparg; i++) {
_PyStackRef value = values[i];
values[i] = PyStackRef_NULL;
if (err == 0) {
err = PySet_Add(set_o, PyStackRef_AsPyObjectBorrow(values[i]));
err = _PySet_AddTakeRef((PySetObject *)set_o, PyStackRef_AsPyObjectSteal(value));
}
else {
PyStackRef_CLOSE(value);
}
}
DECREF_INPUTS();
if (err != 0) {
if (err) {
Py_DECREF(set_o);
ERROR_IF(true, error);
}
INPUTS_DEAD();
set = PyStackRef_FromPyObjectStealMortal(set_o);
}

42
Python/executor_cases.c.h generated
View file

@ -1481,17 +1481,16 @@
v = stack_pointer[-1];
set = stack_pointer[-2 - (oparg-1)];
_PyFrame_SetStackPointer(frame, stack_pointer);
int err = PySet_Add(PyStackRef_AsPyObjectBorrow(set),
PyStackRef_AsPyObjectBorrow(v));
stack_pointer = _PyFrame_GetStackPointer(frame);
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
_PyFrame_SetStackPointer(frame, stack_pointer);
PyStackRef_CLOSE(v);
int err = _PySet_AddTakeRef((PySetObject *)PyStackRef_AsPyObjectBorrow(set),
PyStackRef_AsPyObjectSteal(v));
stack_pointer = _PyFrame_GetStackPointer(frame);
if (err) {
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
JUMP_TO_ERROR();
}
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
break;
}
@ -2687,32 +2686,31 @@
JUMP_TO_ERROR();
}
int err = 0;
for (int i = 0; i < oparg; i++) {
for (Py_ssize_t i = 0; i < oparg; i++) {
_PyStackRef value = values[i];
values[i] = PyStackRef_NULL;
if (err == 0) {
_PyFrame_SetStackPointer(frame, stack_pointer);
err = PySet_Add(set_o, PyStackRef_AsPyObjectBorrow(values[i]));
err = _PySet_AddTakeRef((PySetObject *)set_o, PyStackRef_AsPyObjectSteal(value));
stack_pointer = _PyFrame_GetStackPointer(frame);
}
else {
_PyFrame_SetStackPointer(frame, stack_pointer);
PyStackRef_CLOSE(value);
stack_pointer = _PyFrame_GetStackPointer(frame);
}
}
_PyFrame_SetStackPointer(frame, stack_pointer);
_PyStackRef tmp;
for (int _i = oparg; --_i >= 0;) {
tmp = values[_i];
values[_i] = PyStackRef_NULL;
PyStackRef_CLOSE(tmp);
}
stack_pointer = _PyFrame_GetStackPointer(frame);
stack_pointer += -oparg;
assert(WITHIN_STACK_BOUNDS());
if (err != 0) {
if (err) {
_PyFrame_SetStackPointer(frame, stack_pointer);
Py_DECREF(set_o);
stack_pointer = _PyFrame_GetStackPointer(frame);
stack_pointer += -oparg;
assert(WITHIN_STACK_BOUNDS());
JUMP_TO_ERROR();
}
set = PyStackRef_FromPyObjectStealMortal(set_o);
stack_pointer[0] = set;
stack_pointer += 1;
stack_pointer[-oparg] = set;
stack_pointer += 1 - oparg;
assert(WITHIN_STACK_BOUNDS());
break;
}

42
Python/generated_cases.c.h generated
View file

@ -1110,32 +1110,31 @@
JUMP_TO_LABEL(error);
}
int err = 0;
for (int i = 0; i < oparg; i++) {
for (Py_ssize_t i = 0; i < oparg; i++) {
_PyStackRef value = values[i];
values[i] = PyStackRef_NULL;
if (err == 0) {
_PyFrame_SetStackPointer(frame, stack_pointer);
err = PySet_Add(set_o, PyStackRef_AsPyObjectBorrow(values[i]));
err = _PySet_AddTakeRef((PySetObject *)set_o, PyStackRef_AsPyObjectSteal(value));
stack_pointer = _PyFrame_GetStackPointer(frame);
}
else {
_PyFrame_SetStackPointer(frame, stack_pointer);
PyStackRef_CLOSE(value);
stack_pointer = _PyFrame_GetStackPointer(frame);
}
}
_PyFrame_SetStackPointer(frame, stack_pointer);
_PyStackRef tmp;
for (int _i = oparg; --_i >= 0;) {
tmp = values[_i];
values[_i] = PyStackRef_NULL;
PyStackRef_CLOSE(tmp);
}
stack_pointer = _PyFrame_GetStackPointer(frame);
stack_pointer += -oparg;
assert(WITHIN_STACK_BOUNDS());
if (err != 0) {
if (err) {
_PyFrame_SetStackPointer(frame, stack_pointer);
Py_DECREF(set_o);
stack_pointer = _PyFrame_GetStackPointer(frame);
stack_pointer += -oparg;
assert(WITHIN_STACK_BOUNDS());
JUMP_TO_LABEL(error);
}
set = PyStackRef_FromPyObjectStealMortal(set_o);
stack_pointer[0] = set;
stack_pointer += 1;
stack_pointer[-oparg] = set;
stack_pointer += 1 - oparg;
assert(WITHIN_STACK_BOUNDS());
DISPATCH();
}
@ -10641,17 +10640,14 @@
v = stack_pointer[-1];
set = stack_pointer[-2 - (oparg-1)];
_PyFrame_SetStackPointer(frame, stack_pointer);
int err = PySet_Add(PyStackRef_AsPyObjectBorrow(set),
PyStackRef_AsPyObjectBorrow(v));
stack_pointer = _PyFrame_GetStackPointer(frame);
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
_PyFrame_SetStackPointer(frame, stack_pointer);
PyStackRef_CLOSE(v);
int err = _PySet_AddTakeRef((PySetObject *)PyStackRef_AsPyObjectBorrow(set),
PyStackRef_AsPyObjectSteal(v));
stack_pointer = _PyFrame_GetStackPointer(frame);
if (err) {
JUMP_TO_LABEL(error);
JUMP_TO_LABEL(pop_1_error);
}
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
DISPATCH();
}