diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-05-24-21-04-00.gh-issue-119525.zLFLf1.rst b/Misc/NEWS.d/next/Core and Builtins/2024-05-24-21-04-00.gh-issue-119525.zLFLf1.rst new file mode 100644 index 00000000000..83c29a16e57 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2024-05-24-21-04-00.gh-issue-119525.zLFLf1.rst @@ -0,0 +1,2 @@ +Fix deadlock involving ``_PyType_Lookup()`` cache in the free-threaded build +when the GIL is dynamically enabled at runtime. diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 9d849d83082..290306cdb67 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -5169,7 +5169,7 @@ is_dunder_name(PyObject *name) return 0; } -static void +static PyObject * update_cache(struct type_cache_entry *entry, PyObject *name, unsigned int version_tag, PyObject *value) { _Py_atomic_store_uint32_relaxed(&entry->version, version_tag); @@ -5180,7 +5180,7 @@ update_cache(struct type_cache_entry *entry, PyObject *name, unsigned int versio // exact unicode object or Py_None so it's safe to do so. PyObject *old_name = entry->name; _Py_atomic_store_ptr_relaxed(&entry->name, Py_NewRef(name)); - Py_DECREF(old_name); + return old_name; } #if Py_GIL_DISABLED @@ -5200,10 +5200,12 @@ update_cache_gil_disabled(struct type_cache_entry *entry, PyObject *name, return; } - update_cache(entry, name, version_tag, value); + PyObject *old_value = update_cache(entry, name, version_tag, value); // Then update sequence to the next valid value _PySeqLock_UnlockWrite(&entry->sequence); + + Py_DECREF(old_value); } #endif @@ -5315,7 +5317,8 @@ _PyType_LookupRef(PyTypeObject *type, PyObject *name) #if Py_GIL_DISABLED update_cache_gil_disabled(entry, name, version, res); #else - update_cache(entry, name, version, res); + PyObject *old_value = update_cache(entry, name, version, res); + Py_DECREF(old_value); #endif } return res;