fix(disagg): poll receivers during decode preallocation (#37483)

python/sglang/srt/disaggregation/decode.py

@@ -869,17 +869,8 @@ class DecodePreallocQueue(DecodeHiCachePreallocMixin):
         if not self.queue:
             return
 
-        # Still poll if any receiver was aborted, otherwise it stays stuck.
-        if (
-            self.pp_size <= 1
-            and all(decode_req.waiting_for_input for decode_req in self.queue)
-            and not any(
-                decode_req.kv_receiver.conclude_state == KVPoll.Failed
-                for decode_req in self.queue
-            )
-        ):
-            return
-
+        # Receiver polling observes asynchronous failures while KV allocation
+        # is blocked.
         if self.pp_size > 1:
             polls = poll_and_all_reduce_pp(
                 (decode_req.req.rid for decode_req in self.queue),