From 4c64fffc9179a3f729b71f42e6c679ea15e0a1e8 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 14 Jan 2026 08:25:08 +0000
Subject: [PATCH 1/2] Initial plan


From 710c22c816fddb59a4a9f6191f874063d9f6331b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 14 Jan 2026 08:28:32 +0000
Subject: [PATCH 2/2] Fix race condition in CancelCTS with thread-safe lock

Co-authored-by: weiyuanyue <176483933+weiyuanyue@users.noreply.github.com>
---
 AIDevGallery/Controls/SampleContainer.xaml.cs | 33 ++++++++++++-------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/AIDevGallery/Controls/SampleContainer.xaml.cs b/AIDevGallery/Controls/SampleContainer.xaml.cs
index ccd2ac21..bb6b47c5 100644
--- a/AIDevGallery/Controls/SampleContainer.xaml.cs
+++ b/AIDevGallery/Controls/SampleContainer.xaml.cs
@@ -65,6 +65,7 @@ public List<string> NugetPackageReferences
     private List<ModelDetails>? _modelsCache;
     private WinMlSampleOptions? _currentWinMlSampleOptions;
     private CancellationTokenSource? _sampleLoadingCts;
+    private readonly object _ctsLock = new object();
     private TaskCompletionSource? _sampleLoadedCompletionSource;
     private double _codePaneWidth;
     private ModelType? _wcrApi;
@@ -109,16 +110,19 @@ internal static async Task WaitUnloadAllAsync()
 
     private void CancelCTS()
     {
-        var cts = _sampleLoadingCts;
-        if (cts == null)
+        CancellationTokenSource? cts;
+        lock (_ctsLock)
         {
-            return;
+            cts = _sampleLoadingCts;
+            _sampleLoadingCts = null;
         }
 
-        _sampleLoadingCts = null;
-        using (cts)
+        if (cts != null)
         {
-            cts.Cancel();
+            using (cts)
+            {
+                cts.Cancel();
+            }
         }
     }
 
@@ -220,9 +224,13 @@ public async Task LoadSampleAsync(Sample? sample, List<ModelDetails>? models, Wi
             return;
         }
 
-        _sampleLoadingCts?.Dispose();
-        _sampleLoadingCts = new CancellationTokenSource();
-        var token = _sampleLoadingCts.Token;
+        CancellationToken token;
+        lock (_ctsLock)
+        {
+            _sampleLoadingCts?.Dispose();
+            _sampleLoadingCts = new CancellationTokenSource();
+            token = _sampleLoadingCts.Token;
+        }
 
         // if WCR API, check if model is downloaded
         foreach (var wcrApi in models.Where(m => m.HardwareAccelerators.Contains(HardwareAccelerator.WCRAPI)))
@@ -319,8 +327,11 @@ public async Task LoadSampleAsync(Sample? sample, List<ModelDetails>? models, Wi
         finally
         {
             _sampleLoadedCompletionSource = null;
-            _sampleLoadingCts?.Dispose();
-            _sampleLoadingCts = null;
+            lock (_ctsLock)
+            {
+                _sampleLoadingCts?.Dispose();
+                _sampleLoadingCts = null;
+            }
         }
 
         NavigatedToSampleLoadedEvent.Log(sample.Name ?? string.Empty);