diff --git a/tractor/_runtime.py b/tractor/_runtime.py
index 30ba1f4..9f8fed0 100644
--- a/tractor/_runtime.py
+++ b/tractor/_runtime.py
@@ -740,7 +740,7 @@ class Actor:
                             f'STALE DEBUG LOCK DETECTED FOR {uid}'
                         )
                         # TODO: figure out why this breaks tests..
-                        pdb_lock._root_local_task_cs_in_debug.cancel()
+                        db_cs.cancel()
 
             # XXX: is this necessary (GC should do it)?
             if chan.connected():