diff --git a/Python/instrumentation.c b/Python/instrumentation.c
index 0af2070b5cd983..806d3fbf5d6b19 100644
--- a/Python/instrumentation.c
+++ b/Python/instrumentation.c
@@ -989,8 +989,12 @@ call_one_instrument(
     if (res == NULL) {
         return -1;
     }
+    if (res == &_PyInstrumentation_DISABLE) {
+        assert(_Py_IsImmortal(res));
+        return 1;
+    }
     Py_DECREF(res);
-    return (res == &_PyInstrumentation_DISABLE);
+    return 0;
 }
 
 static const int8_t MOST_SIGNIFICANT_BITS[16] = {