From c5a46fda448c943aef48f9e477330af02f89a0a8 Mon Sep 17 00:00:00 2001
From: Wang Qi <wangq8@outlook.com>
Date: Thu, 21 May 2026 19:23:41 +0800
Subject: [PATCH] Fix: <asyncio.locks.Semaphore object at 0xabcd [locked]> is
 bound to a different event loop (#15100)

Fix: <asyncio.locks.Semaphore object at 0xabcd [locked]> is bound to a
different event loop
---
 common/asyncio_utils.py  | 56 ++++++++++++++++++++++++++++++++++++++++
 rag/graphrag/utils.py    |  3 ++-
 rag/svr/task_executor.py | 11 ++++----
 3 files changed, 64 insertions(+), 6 deletions(-)
 create mode 100644 common/asyncio_utils.py

diff --git a/common/asyncio_utils.py b/common/asyncio_utils.py
new file mode 100644
index 0000000000..12f5e0220a
--- /dev/null
+++ b/common/asyncio_utils.py
@@ -0,0 +1,56 @@
+#
+#  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+import asyncio
+import weakref
+
+
+class LoopLocalSemaphore:
+    """
+    Asyncio synchronization primitives bind to the event loop that waits on them.
+    Keep one semaphore per running loop for module-level concurrency limiters.
+    """
+
+    def __init__(self, value: int):
+        self._value = int(value)
+        self._semaphores: "weakref.WeakKeyDictionary[asyncio.AbstractEventLoop, asyncio.Semaphore]" = (
+            weakref.WeakKeyDictionary()
+        )
+
+    def _get(self) -> asyncio.Semaphore:
+        loop = asyncio.get_running_loop()
+        for cached_loop in list(self._semaphores):
+            if cached_loop.is_closed():
+                self._semaphores.pop(cached_loop, None)
+        sem = self._semaphores.get(loop)
+        if sem is None:
+            sem = asyncio.Semaphore(self._value)
+            self._semaphores[loop] = sem
+        return sem
+
+    async def acquire(self) -> bool:
+        return await self._get().acquire()
+
+    def release(self) -> None:
+        self._get().release()
+
+    async def __aenter__(self):
+        await self.acquire()
+        return self
+
+    async def __aexit__(self, exc_type, exc, tb):
+        self.release()
+        return False
diff --git a/rag/graphrag/utils.py b/rag/graphrag/utils.py
index fa29ebe389..c92fe0c6fe 100644
--- a/rag/graphrag/utils.py
+++ b/rag/graphrag/utils.py
@@ -28,6 +28,7 @@ from networkx.readwrite import json_graph
 
 from common.misc_utils import get_uuid
 from common.connection_utils import timeout
+from common.asyncio_utils import LoopLocalSemaphore
 from rag.nlp import rag_tokenizer, search
 from rag.utils.redis_conn import REDIS_CONN
 from common import settings
@@ -37,7 +38,7 @@ GRAPH_FIELD_SEP = "<SEP>"
 
 ErrorHandlerFn = Callable[[BaseException | None, str | None, dict | None], None]
 
-chat_limiter = asyncio.Semaphore(int(os.environ.get("MAX_CONCURRENT_CHATS", 10)))
+chat_limiter = LoopLocalSemaphore(int(os.environ.get("MAX_CONCURRENT_CHATS", 10)))
 
 # Doc-store insert batching for GraphRAG subgraph/node/edge/community_report
 # chunks.  Defaults (64 docs per batch, up to 4 batches in flight) mirror the
diff --git a/rag/svr/task_executor.py b/rag/svr/task_executor.py
index e639ba6e46..9e263e8b5a 100644
--- a/rag/svr/task_executor.py
+++ b/rag/svr/task_executor.py
@@ -89,6 +89,7 @@ from rag.utils.redis_conn import REDIS_CONN, RedisDistributedLock
 from rag.graphrag.utils import chat_limiter
 from common.signal_utils import start_tracemalloc_and_snapshot, stop_tracemalloc
 from common.exceptions import TaskCanceledException
+from common.asyncio_utils import LoopLocalSemaphore
 from common import settings
 from common.constants import PAGERANK_FLD, TAG_FLD, SVR_CONSUMER_GROUP_NAME
 from rag.utils.table_es_metadata import (
@@ -142,11 +143,11 @@ CURRENT_TASKS = {}
 MAX_CONCURRENT_TASKS = int(os.environ.get('MAX_CONCURRENT_TASKS', "5"))
 MAX_CONCURRENT_CHUNK_BUILDERS = int(os.environ.get('MAX_CONCURRENT_CHUNK_BUILDERS', "1"))
 MAX_CONCURRENT_MINIO = int(os.environ.get('MAX_CONCURRENT_MINIO', '10'))
-task_limiter = asyncio.Semaphore(MAX_CONCURRENT_TASKS)
-chunk_limiter = asyncio.Semaphore(MAX_CONCURRENT_CHUNK_BUILDERS)
-embed_limiter = asyncio.Semaphore(MAX_CONCURRENT_CHUNK_BUILDERS)
-minio_limiter = asyncio.Semaphore(MAX_CONCURRENT_MINIO)
-kg_limiter = asyncio.Semaphore(2)
+task_limiter = LoopLocalSemaphore(MAX_CONCURRENT_TASKS)
+chunk_limiter = LoopLocalSemaphore(MAX_CONCURRENT_CHUNK_BUILDERS)
+embed_limiter = LoopLocalSemaphore(MAX_CONCURRENT_CHUNK_BUILDERS)
+minio_limiter = LoopLocalSemaphore(MAX_CONCURRENT_MINIO)
+kg_limiter = LoopLocalSemaphore(2)
 WORKER_HEARTBEAT_TIMEOUT = int(os.environ.get('WORKER_HEARTBEAT_TIMEOUT', '120'))
 stop_event = threading.Event()