diff --git a/trpc/coroutine/fiber_blocking_noncontiguous_buffer.h b/trpc/coroutine/fiber_blocking_noncontiguous_buffer.h
index 41d1d9e5..59bd1e24 100644
--- a/trpc/coroutine/fiber_blocking_noncontiguous_buffer.h
+++ b/trpc/coroutine/fiber_blocking_noncontiguous_buffer.h
@@ -145,7 +145,10 @@ class FiberBlockingNoncontiguousBuffer {
   }
 
   void Stop() {
-    stop_token_ = true;
+    {
+      std::lock_guard lk(mutex_);
+      stop_token_ = true;
+    }
     not_full_.notify_one();
     not_empty_.notify_one();
   }