Use an atomic load.

ZeroIntensity · ZeroIntensity · commit ff426797300e · 2025-03-25T13:20:21.000Z
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
@@ -4577,7 +4577,7 @@ dict_traverse(PyObject *op, visitproc visit, void *arg)
 
     if (DK_IS_UNICODE(keys)) {
         if (_PyDict_HasSplitTable(mp)) {
-            if (mp->ma_values->valid) {
+            if (!FT_ATOMIC_LOAD_UINT8(mp->ma_values->valid)) {
                 for (i = 0; i < n; i++) {
                     Py_VISIT(mp->ma_values->values[i]);
                 }

Original file line number	Diff line number	Diff line change
`@@ -4577,7 +4577,7 @@ dict_traverse(PyObject op, visitproc visit, void arg)`
`4577`	`4577`
`4578`	`4578`	`if (DK_IS_UNICODE(keys)) {`
`4579`	`4579`	`if (_PyDict_HasSplitTable(mp)) {`
`4580`		`- if (mp->ma_values->valid) {`
	`4580`	`+ if (!FT_ATOMIC_LOAD_UINT8(mp->ma_values->valid)) {`
`4581`	`4581`	`for (i = 0; i < n; i++) {`
`4582`	`4582`	`Py_VISIT(mp->ma_values->values[i]);`
`4583`	`4583`	`}`