From a391144abdca91c841ae05762540a604753886cd Mon Sep 17 00:00:00 2001
From: Cyberboss <Cyberboss@users.noreply.github.com>
Date: Sun, 31 May 2020 16:44:22 -0400
Subject: [PATCH] Fix potential concurrency issue when reattaching

---
 .../Components/Session/SessionController.cs                  | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/Tgstation.Server.Host/Components/Session/SessionController.cs b/src/Tgstation.Server.Host/Components/Session/SessionController.cs
index 471cbad030..f8740a0034 100644
--- a/src/Tgstation.Server.Host/Components/Session/SessionController.cs
+++ b/src/Tgstation.Server.Host/Components/Session/SessionController.cs
@@ -241,8 +241,9 @@ namespace Tgstation.Server.Host.Components.Session
 			_ = process.Lifetime.ContinueWith(
 				x =>
 				{
-					if (!disposed)
-						reattachTopicCts.Cancel();
+					lock (synchronizationLock)
+						if (!disposed)
+							reattachTopicCts.Cancel();
 					chatTrackingContext.Active = false;
 				},
 				TaskScheduler.Current);