Skip to content

gh-127536: Add missing locks in listobject.c #127580

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Dec 4, 2024
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Add missing locks around some list assignment operations in the free
threading build.
50 changes: 40 additions & 10 deletions Objects/listobject.c
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
#include "pycore_ceval.h" // _PyEval_GetBuiltin()
#include "pycore_critical_section.h" // _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED()
#include "pycore_dict.h" // _PyDictViewObject
#include "pycore_freelist.h" // _Py_FREELIST_FREE(), _Py_FREELIST_POP()
#include "pycore_pyatomic_ft_wrappers.h"
Expand Down Expand Up @@ -72,6 +73,11 @@ static void
ensure_shared_on_resize(PyListObject *self)
{
#ifdef Py_GIL_DISABLED
// We can't use _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED here because
// the `CALL_LIST_APPEND` bytecode handler may lock the list without
// a critical section.
assert(Py_REFCNT(self) == 1 || PyMutex_IsLocked(&_PyObject_CAST(self)->ob_mutex));

// Ensure that the list array is freed using QSBR if we are not the
// owning thread.
if (!_Py_IsOwnedByCurrentThread((PyObject *)self) &&
Expand Down Expand Up @@ -957,10 +963,12 @@ list_ass_slice(PyListObject *a, Py_ssize_t ilow, Py_ssize_t ihigh, PyObject *v)
Py_ssize_t n = PyList_GET_SIZE(a);
PyObject *copy = list_slice_lock_held(a, 0, n);
if (copy == NULL) {
return -1;
ret = -1;
}
else {
ret = list_ass_slice_lock_held(a, ilow, ihigh, copy);
Py_DECREF(copy);
}
ret = list_ass_slice_lock_held(a, ilow, ihigh, copy);
Py_DECREF(copy);
Py_END_CRITICAL_SECTION();
}
else if (v != NULL && PyList_CheckExact(v)) {
Expand Down Expand Up @@ -1437,7 +1445,9 @@ PyList_Clear(PyObject *self)
PyErr_BadInternalCall();
return -1;
}
Py_BEGIN_CRITICAL_SECTION(self);
list_clear((PyListObject*)self);
Py_END_CRITICAL_SECTION();
return 0;
}

Expand Down Expand Up @@ -3410,7 +3420,9 @@ list___init___impl(PyListObject *self, PyObject *iterable)

/* Empty previous contents */
if (self->ob_item != NULL) {
Py_BEGIN_CRITICAL_SECTION(self);
list_clear(self);
Py_END_CRITICAL_SECTION();
}
if (iterable != NULL) {
if (_list_extend(self, iterable) < 0) {
Expand Down Expand Up @@ -3583,16 +3595,18 @@ adjust_slice_indexes(PyListObject *lst,
}

static int
list_ass_subscript(PyObject* _self, PyObject* item, PyObject* value)
list_ass_subscript_lock_held(PyObject *_self, PyObject *item, PyObject *value)
{
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(_self);

PyListObject *self = (PyListObject *)_self;
if (_PyIndex_Check(item)) {
Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
if (i == -1 && PyErr_Occurred())
return -1;
if (i < 0)
i += PyList_GET_SIZE(self);
return list_ass_item((PyObject *)self, i, value);
return list_ass_item_lock_held(self, i, value);
}
else if (PySlice_Check(item)) {
Py_ssize_t start, stop, step;
Expand All @@ -3612,7 +3626,7 @@ list_ass_subscript(PyObject* _self, PyObject* item, PyObject* value)
step);

if (step == 1)
return list_ass_slice(self, start, stop, value);
return list_ass_slice_lock_held(self, start, stop, value);

if (slicelength <= 0)
return 0;
Expand Down Expand Up @@ -3678,10 +3692,8 @@ list_ass_subscript(PyObject* _self, PyObject* item, PyObject* value)

/* protect against a[::-1] = a */
if (self == (PyListObject*)value) {
Py_BEGIN_CRITICAL_SECTION(value);
seq = list_slice_lock_held((PyListObject*)value, 0,
seq = list_slice_lock_held((PyListObject *)value, 0,
Py_SIZE(value));
Py_END_CRITICAL_SECTION();
}
else {
seq = PySequence_Fast(value,
Expand All @@ -3695,7 +3707,7 @@ list_ass_subscript(PyObject* _self, PyObject* item, PyObject* value)
step);

if (step == 1) {
int res = list_ass_slice(self, start, stop, seq);
int res = list_ass_slice_lock_held(self, start, stop, seq);
Py_DECREF(seq);
return res;
}
Expand Down Expand Up @@ -3751,6 +3763,24 @@ list_ass_subscript(PyObject* _self, PyObject* item, PyObject* value)
}
}

static int
list_ass_subscript(PyObject *self, PyObject *item, PyObject *value)
{
int res;
#ifdef Py_GIL_DISABLED
if (PySlice_Check(item) && value != NULL && PyList_CheckExact(value)) {
Py_BEGIN_CRITICAL_SECTION2(self, value);
res = list_ass_subscript_lock_held(self, item, value);
Py_END_CRITICAL_SECTION2();
return res;
}
#endif
Py_BEGIN_CRITICAL_SECTION(self);
res = list_ass_subscript_lock_held(self, item, value);
Py_END_CRITICAL_SECTION();
return res;
}

static PyMappingMethods list_as_mapping = {
list_length,
list_subscript,
Expand Down
Loading