Document conflicting read

Author: mpage

Objects/dictobject.c

@@ -7803,6 +7803,8 @@ clear_inline_values(PyDictValues *values)
         FT_ATOMIC_STORE_UINT8(values->valid, 0);
         for (Py_ssize_t i = 0; i < values->capacity; i++) {
             PyObject *value = values->values[i];
+            // The attribute read fast-path may read these without holding the
+            // per-object lock.
             FT_ATOMIC_STORE_PTR_RELEASE(values->values[i], NULL);
             Py_XDECREF(value);
         }