diff --git a/src/Servers/Kestrel/test/InMemory.FunctionalTests/TestTransport/InMemoryTransportConnection.cs b/src/Servers/Kestrel/test/InMemory.FunctionalTests/TestTransport/InMemoryTransportConnection.cs
index b6f510a722a4..086694908360 100644
--- a/src/Servers/Kestrel/test/InMemory.FunctionalTests/TestTransport/InMemoryTransportConnection.cs
+++ b/src/Servers/Kestrel/test/InMemory.FunctionalTests/TestTransport/InMemoryTransportConnection.cs
@@ -63,13 +63,11 @@ public override void Abort(ConnectionAbortedException abortReason)
 
     public void OnClosed()
     {
-        if (_isClosed)
+        if (Interlocked.CompareExchange(ref _isClosed, true, false) == true)
         {
             return;
         }
 
-        _isClosed = true;
-
         ThreadPool.UnsafeQueueUserWorkItem(state =>
         {
             state._connectionClosedTokenSource.Cancel();