gh-120321: Fix TSan reported race in gen_clear_frame (gh-142995)

TSan treats compare-exchanges that fail as if they are writes
so there is a false positive with the read of gi_frame_state in
gen_close.

diff --git a/Objects/genobject.c b/Objects/genobject.c
index 508d215a0cfe64a00f1511b2a4d75801a123a2c6..1e59d89f5ce85fe337035806dd7cb0098a4dcdb0 100644 (file)
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -153,7 +153,7 @@ _PyGen_Finalize(PyObject *self)
 static void
 gen_clear_frame(PyGenObject *gen)
 {
-    assert(gen->gi_frame_state == FRAME_CLEARED);
+    assert(FT_ATOMIC_LOAD_INT8_RELAXED(gen->gi_frame_state) == FRAME_CLEARED);
     _PyInterpreterFrame *frame = &gen->gi_iframe;
     frame->previous = NULL;
     _PyFrame_ClearExceptCode(frame);