Skip to content

gh-145685: Stop the world when updating MRO of existing types#145707

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.

Sign up for GitHub

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
colesbury merged 1 commit into from
Mar 9, 2026
Merged

gh-145685: Stop the world when updating MRO of existing types #145707

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
25 changes: 14 additions & 11 deletions Objects/typeobject.c
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -647,7 +647,6 @@ clear_tp_bases(PyTypeObject *self, int final)
static inline PyObject *
lookup_tp_mro(PyTypeObject *self)
{
ASSERT_NEW_TYPE_OR_LOCKED(self);
return self->tp_mro;
}

Expand All@@ -664,8 +663,19 @@ set_tp_mro(PyTypeObject *self, PyObject *mro, int initial)
/* Other checks are done via set_tp_bases. */
_Py_SetImmortal(mro);
}
else {
PyUnstable_Object_EnableDeferredRefcount(mro);
}
}
if (!initial) {
type_lock_prevent_release();
types_stop_world();
}
self->tp_mro = mro;
if (!initial) {
types_start_world();
type_lock_allow_release();
}
}

static inline void
Expand DownExpand Up@@ -1728,18 +1738,11 @@ static PyObject *
type_get_mro(PyObject *tp, void *Py_UNUSED(closure))
{
PyTypeObject *type = PyTypeObject_CAST(tp);
PyObject *mro;

BEGIN_TYPE_LOCK();
mro = lookup_tp_mro(type);
PyObject *mro = lookup_tp_mro(type);
if (mro == NULL) {
mro = Py_None;
} else {
Py_INCREF(mro);
Py_RETURN_NONE;
}

END_TYPE_LOCK();
return mro;
return Py_NewRef(mro);
}

static PyTypeObject *find_best_base(PyObject *);
Expand Down
Loading