Update

Modules/_abc.c

@@ -875,14 +875,17 @@ subclasscheck_check_registry(_abc_data *impl, PyObject *subclass,
         if (PyWeakref_GetRef(key, &rkey) < 0) {
             // Someone inject non-weakref type in the registry.
             ret = -1;
+            Py_DECREF(key);
             break;
         }
 
         if (rkey == NULL) {
+            Py_DECREF(key);
             continue;
         }
         int r = PyObject_IsSubclass(subclass, rkey);
         Py_DECREF(rkey);
+        Py_DECREF(key);
         if (r < 0) {
             ret = -1;
             break;

Modules/_pickle.c

@@ -3418,7 +3418,6 @@ save_set(PickleState *state, PicklerObject *self, PyObject *obj)
         int err = 0;
         Py_BEGIN_CRITICAL_SECTION(obj);
         while (_PySet_NextEntry(obj, &ppos, &item, &hash)) {
-            Py_INCREF(item);
             err = save(state, self, item, 0);
             Py_CLEAR(item);
             if (err < 0)

Objects/codeobject.c

@@ -2352,12 +2352,14 @@ _PyCode_ConstantKey(PyObject *op)
 
             item_key = _PyCode_ConstantKey(item);
             if (item_key == NULL) {
+                Py_DECREF(item);
                 Py_DECREF(tuple);
                 return NULL;
             }
 
             assert(i < len);
             PyTuple_SET_ITEM(tuple, i, item_key);
+            Py_DECREF(item);
             i++;
         }
         set = PyFrozenSet_New(tuple);

Objects/dictobject.c

@@ -2981,7 +2981,7 @@ dict_set_fromkeys(PyInterpreterState *interp, PyDictObject *mp,
 
     _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(iterable);
     while (_PySet_NextEntry(iterable, &pos, &key, &hash)) {
-        if (insertdict(interp, mp, Py_NewRef(key), hash, Py_NewRef(value))) {
+        if (insertdict(interp, mp, key, hash, Py_NewRef(value))) {
             Py_DECREF(mp);
             mp = NULL;
             break;

Objects/listobject.c

@@ -1289,7 +1289,6 @@ list_extend_set(PyListObject *self, PySetObject *other)
     PyObject **dest = self->ob_item + m;
     Py_BEGIN_CRITICAL_SECTION(other);
     while (_PySet_NextEntry((PyObject *)other, &setpos, &key, &hash)) {
-        Py_INCREF(key);
         FT_ATOMIC_STORE_PTR_RELEASE(*dest, key);
         dest++;
     }

Objects/setobject.c

@@ -2669,7 +2669,7 @@ _PySet_NextEntry_lock_held(PyObject *set, Py_ssize_t *pos, PyObject **key, Py_ha
     if (ret == 0) {
         return 0;
     }
-    *key = entry->key;
+    *key = Py_NewRef(entry->key);
     *hash = entry->hash;
     return 1;
 }

Python/compile.c

@@ -922,6 +922,7 @@ merge_consts_recursive(PyObject *const_cache, PyObject *o)
         Py_hash_t hash;
         while (_PyFrozenSet_NextEntry(o, &pos, &item, &hash)) {
             PyObject *k = merge_consts_recursive(const_cache, item);
+            Py_DECREF(item);
             if (k == NULL) {
                 Py_DECREF(tuple);
                 Py_DECREF(key);

Python/marshal.c

@@ -542,6 +542,7 @@ w_complex_object(PyObject *v, char flag, WFILE *p)
             }
             PyObject *pair = PyTuple_Pack(2, dump, value);
             Py_DECREF(dump);
+            Py_DECREF(value);
             if (pair == NULL) {
                 p->error = WFERR_NOMEMORY;
                 break;

Python/pylifecycle.c

@@ -2916,6 +2916,7 @@ _Py_DumpExtensionModules(int fd, PyInterpreterState *interp)
                     && PyUnicode_Compare(key, item) == 0)
                 {
                     is_stdlib_ext = 1;
+                    Py_DECREF(item);
                     break;
                 }
             }