diff --git a/torchdata/dataloader2/reading_service.py b/torchdata/dataloader2/reading_service.py
index f9c2baa85..0cfcb367c 100644
--- a/torchdata/dataloader2/reading_service.py
+++ b/torchdata/dataloader2/reading_service.py
@@ -204,6 +204,8 @@ def _resume(self):
         Resumes DataPipes' activities. This is required to be called after `_pause` before
         the DataLoader can keep yielding elements.
         """
+        assert self._end_datapipe is not None
+
         dp_list = list_dps(traverse_dps(self._end_datapipe))
         # Reversed order
         for dp in dp_list[::-1]:
@@ -435,6 +437,7 @@ def _pause(self):
         in order to collect state.
         """
         assert self._end_datapipe is not None
+
         dp_list = list_dps(traverse_dps(self._end_datapipe))
         for dp in dp_list:
             # TODO: Combine QueueWrapper and _IterateQueueDataPipes,
@@ -451,6 +454,8 @@ def _resume(self):
         Resumes DataPipes' activities. This is required to be called after `_pause` before
         the DataLoader can keep yielding elements.
         """
+        assert self._end_datapipe is not None
+
         self._worker_consumer_datapipe.request_resume()  # type: ignore[union-attr]
         dp_list = list_dps(traverse_dps(self._end_datapipe))
         # Reversed order