From 64225a8ae9989bb58112403fa5a7ed2e51661a63 Mon Sep 17 00:00:00 2001
From: luchangli <liluchang@kingsoft.com>
Date: Tue, 25 Nov 2025 21:40:11 +0800
Subject: [PATCH] fix nixl prefill crash make decode health check failed
 (#13657)

Signed-off-by: liluchang <liluchang@kingsoft.com>
---
 python/sglang/srt/disaggregation/nixl/conn.py | 48 +++++++++++++------
 1 file changed, 34 insertions(+), 14 deletions(-)

diff --git a/python/sglang/srt/disaggregation/nixl/conn.py b/python/sglang/srt/disaggregation/nixl/conn.py
index c61c3e980..622bfc03f 100644
--- a/python/sglang/srt/disaggregation/nixl/conn.py
+++ b/python/sglang/srt/disaggregation/nixl/conn.py
@@ -155,6 +155,9 @@ class NixlKVManager(CommonKVManager):
             self.max_failures = max(
                 get_int_env_var("SGLANG_DISAGGREGATION_HEARTBEAT_MAX_FAILURE", 2), 1
             )
+            self.waiting_timeout = get_int_env_var(
+                "SGLANG_DISAGGREGATION_WAITING_TIMEOUT", 300
+            )
             self._start_heartbeat_checker_thread()
         else:
             raise ValueError(
@@ -186,16 +189,6 @@ class NixlKVManager(CommonKVManager):
                         if response.status_code == 200:
                             self.heartbeat_failures[bootstrap_addr] = 0
 
-                            current_rooms = self.addr_to_rooms_tracker[
-                                bootstrap_addr
-                            ].copy()
-
-                            for bootstrap_room in current_rooms:
-                                # Remove successful transfers from the tracker
-                                if bootstrap_room not in self.transfer_statuses:
-                                    self.addr_to_rooms_tracker[bootstrap_addr].discard(
-                                        bootstrap_room
-                                    )
                         else:
                             logger.info(
                                 f"Attempting to reconnect to {bootstrap_addr}..."
@@ -259,6 +252,9 @@ class NixlKVManager(CommonKVManager):
             f"Lost connection with prefill instance (bootstrap_addr: {failed_bootstrap_addr}), "
             f"{len(affected_rooms)} transfers affected"
         )
+        for room in possible_affected_rooms:
+            logger.error(f"Let room {room} be failed due to prefill down")
+            self.update_status(room, KVPoll.Failed)
 
     def check_status(self, bootstrap_room: int):
         return self.request_status[bootstrap_room]
@@ -267,10 +263,13 @@ class NixlKVManager(CommonKVManager):
         if bootstrap_room not in self.request_status:
             self.request_status[bootstrap_room] = status
         else:
-            # NOTE: The prefill engine could recv bootstrapping first
-            self.request_status[bootstrap_room] = max(
-                self.request_status[bootstrap_room], status
-            )
+            # NOTE: status is only allowed to be incremented unless it is KVPoll.Failed
+            if status == KVPoll.Failed:
+                self.request_status[bootstrap_room] = KVPoll.Failed
+            else:
+                self.request_status[bootstrap_room] = max(
+                    self.request_status[bootstrap_room], status
+                )
 
     def record_failure(self, bootstrap_room: int, failure_reason: str):
         pass
@@ -752,6 +751,7 @@ class NixlKVReceiver(CommonKVReceiver):
             self.kv_mgr.addr_to_rooms_tracker[self.bootstrap_addr].add(
                 self.bootstrap_room
             )
+        self.init_time = None
 
     def init(
         self,
@@ -790,15 +790,35 @@ class NixlKVReceiver(CommonKVReceiver):
                 )
 
         self.started_transfer = True
+        self.init_time = time.time()
 
     def poll(self) -> KVPoll:
         if self.conclude_state is not None:
             return self.conclude_state
+        status = self.kv_mgr.check_status(self.bootstrap_room)
+        if status in (KVPoll.Success, KVPoll.Failed):
+            self.conclude_state = status
+            return status
         if not self.started_transfer:
             return KVPoll.WaitingForInput  # type: ignore
 
+        now = time.time()
+        elapsed = now - self.init_time
+
+        if elapsed >= self.kv_mgr.waiting_timeout:
+            logger.error(f"Request {self.bootstrap_room} waiting_timeout")
+            self.kv_mgr.record_failure(
+                self.bootstrap_room,
+                f"Request {self.bootstrap_room} timed out after {elapsed:.1f}s in KVPoll.WaitingForInput",
+            )
+            self.conclude_state = KVPoll.Failed
+            return KVPoll.Failed
+
         self.kv_mgr.update_transfer_status()
         if self.kv_mgr.check_transfer_done(self.bootstrap_room):  # type: ignore
+            self.kv_mgr.addr_to_rooms_tracker[self.bootstrap_addr].discard(
+                self.bootstrap_room
+            )
             # Check if the transfer failed
             if self.kv_mgr.transfer_statuses[self.bootstrap_room].is_failed():
                 self.conclude_state = KVPoll.Failed