https://github.com/python/cpython/commit/77632f085d0cec29c7576b8528849276109801a1
commit: 77632f085d0cec29c7576b8528849276109801a1
branch: main
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2026-03-16T14:19:00+01:00
summary:
gh-141510: Avoid critical section on frozendict copy (#145920)
files:
M Objects/dictobject.c
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 842d9be73b8792..08e40bf84c42fa 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -968,7 +968,9 @@ clone_combined_dict_keys(PyDictObject *orig)
assert(orig->ma_keys != Py_EMPTY_KEYS);
assert(orig->ma_keys->dk_refcnt == 1);
- ASSERT_DICT_LOCKED(orig);
+ if (!PyFrozenDict_Check(orig)) {
+ ASSERT_DICT_LOCKED(orig);
+ }
size_t keys_size = _PyDict_KeysSize(orig->ma_keys);
PyDictKeysObject *keys = PyMem_Malloc(keys_size);
@@ -4322,7 +4324,10 @@ copy_lock_held(PyObject *o, int as_frozendict)
PyObject *copy;
PyDictObject *mp;
- ASSERT_DICT_LOCKED(o);
+ // frozendict is immutable and so doesn't need critical section
+ if (!PyFrozenDict_Check(o)) {
+ ASSERT_DICT_LOCKED(o);
+ }
mp = (PyDictObject *)o;
if (mp->ma_used == 0) {
@@ -4445,9 +4450,14 @@ anydict_copy(PyObject *o)
assert(PyAnyDict_Check(o));
PyObject *res;
- Py_BEGIN_CRITICAL_SECTION(o);
- res = copy_lock_held(o, PyFrozenDict_Check(o));
- Py_END_CRITICAL_SECTION();
+ if (PyFrozenDict_Check(o)) {
+ res = copy_lock_held(o, 1);
+ }
+ else {
+ Py_BEGIN_CRITICAL_SECTION(o);
+ res = copy_lock_held(o, 0);
+ Py_END_CRITICAL_SECTION();
+ }
return res;
}
@@ -4459,9 +4469,14 @@ _PyDict_CopyAsDict(PyObject *o)
assert(PyAnyDict_Check(o));
PyObject *res;
- Py_BEGIN_CRITICAL_SECTION(o);
- res = copy_lock_held(o, 0);
- Py_END_CRITICAL_SECTION();
+ if (PyFrozenDict_Check(o)) {
+ res = copy_lock_held(o, 0);
+ }
+ else {
+ Py_BEGIN_CRITICAL_SECTION(o);
+ res = copy_lock_held(o, 0);
+ Py_END_CRITICAL_SECTION();
+ }
return res;
}
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