diff --git a/vllm/distributed/device_communicators/custom_all_reduce.py b/vllm/distributed/device_communicators/custom_all_reduce.py
index d50d557a9545b..dd6f200962351 100644
--- a/vllm/distributed/device_communicators/custom_all_reduce.py
+++ b/vllm/distributed/device_communicators/custom_all_reduce.py
@@ -198,6 +198,8 @@ def _get_ipc_tensors(self, inp: torch.Tensor) -> List[torch.Tensor]:
         for i, obj in enumerate(all_meta):
             func = obj[0][0]
             args = list(obj[0][1])
+            # This might break in the future since what `args` encompasses
+            # may change.
             args[6] = inp.device.index
             if i != self.rank:
                 all_tensors.append(func(*args))