diff --git a/core/Pool/Pool.php b/core/Pool/Pool.php
index 8f7b594b..ab6d3a0d 100644
--- a/core/Pool/Pool.php
+++ b/core/Pool/Pool.php
@@ -47,6 +47,7 @@ class Pool extends Component
     protected function pop(Channel $channel, $retain_number): void
     {
         if ($channel instanceof Channel && Coroutine::getCid() === -1) {
+            $channel = null;
             unset($channel);
             return;
         }