Force MultiThreaded execution mode and remove SingleThread option

.github/workflows/ci.yml

@@ -86,7 +86,7 @@ jobs:
             # macOS runner performance has gotten unbearably slow so let's turn them off temporarily.
             # - { prettyname: macOS, fullname: macos-latest }
             - { prettyname: Linux, fullname: ubuntu-latest }
-          threadingMode: ['SingleThread', 'MultiThreaded']
+          threadingMode: ['MultiThreaded']
     timeout-minutes: 120
     steps:
       - name: Checkout

README.md

@@ -160,7 +160,6 @@ Settings → Graphics → Renderer now exposes the full set of fork-added option
 | **Renderer** | Picks the GPU backend. On Windows you get Metal / Vulkan / D3D11 / **D3D12 (new)** / OpenGL plus their `Deferred_*` experimental variants. On Android you get Vulkan (if supported) and OpenGL ES. |
 | **Frame limiter** | VSync, **VSync Unbuffered (new)** — ideal for G-Sync / FreeSync / VRR displays, 2×/4×/8× refresh, Unlimited, or **Custom (new)**. |
 | **Custom draw rate limit** | Slider 0–1000 Hz, only visible when the frame limiter is set to Custom. `0` = unlimited draw thread. Useful for benchmarking or VRR-specific tuning. |
-| **Threading mode** | Single / MultiThreaded / MultiThreadedDrawing. |
 | **Low latency** | `Off` / `On` / `Boost` — drives the fork's generic `ILowLatencyProvider` (NVIDIA Reflex / LatencyFlex-ready on D3D11 & D3D12; no-op on other backends until a provider plugin is supplied). `Boost` also sleeps at the start of each update frame for lower input-to-photon latency. |
 
 ---
@@ -184,6 +183,7 @@ Settings → Graphics → Renderer now exposes the full set of fork-added option
 
 This fork includes several hardening fixes on top of upstream:
 
+- **Multi-threaded execution lock-in (v145+)** — the framework's `ExecutionMode = SingleThread` is force-set to `MultiThreaded` on every startup and the threading-mode toggle is removed from Settings → Graphics → Renderer. SingleThread on Android collapsed the SDL/Vulkan thread onto the same thread that delivers the `SurfaceHolder.Callback`, so `VeldridDevice`'s 5-second `SurfaceHandle` poll deadlocked and Vulkan device creation crashed on a null function pointer (`SDLThread` `SI_TKILL` ~5 s into launch). The same risk applies to iOS Metal drawable attach; on desktop SingleThread is strictly slower with no UX benefit, so the lock-in is unconditional across all platforms.
 - **Sentry-safe init** — the app gracefully handles a missing/placeholder Sentry DSN instead of failing on startup
 - **Graceful native library loading** — if the Oboe or Vulkan native libraries are missing, the app continues without them
 - **JNI surface safety** — proper lifecycle management with atomic swaps and timeouts to prevent race conditions between Android surface creation and destruction

osu.Game.Tests/Visual/Navigation/TestSceneOsuGame.cs

@@ -8,9 +8,7 @@
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
-using osu.Framework.Configuration;
 using osu.Framework.Graphics.Textures;
-using osu.Framework.Platform;
 using osu.Game.Audio;
 using osu.Game.Beatmaps;
 using osu.Game.Configuration;
@@ -104,13 +102,6 @@ public void TestNullRulesetHandled()
             AddAssert("ruleset unchanged", () => ReferenceEquals(Ruleset.Value, ruleset));
         }
 
-        [Test]
-        public void TestSwitchThreadExecutionMode()
-        {
-            AddStep("Change thread mode to multi threaded", () => { Game.Dependencies.Get<FrameworkConfigManager>().SetValue(FrameworkSetting.ExecutionMode, ExecutionMode.MultiThreaded); });
-            AddStep("Change thread mode to single thread", () => { Game.Dependencies.Get<FrameworkConfigManager>().SetValue(FrameworkSetting.ExecutionMode, ExecutionMode.SingleThread); });
-        }
-
         [Test]
         public void TestUnavailableRulesetHandled()
         {

osu.Game/Localisation/GraphicsSettingsStrings.cs

@@ -29,11 +29,6 @@ public static class GraphicsSettingsStrings
         /// </summary>
         public static LocalisableString FrameLimiter => new TranslatableString(getKey(@"frame_limiter"), @"Frame limiter");
 
-        /// <summary>
-        /// "Threading mode"
-        /// </summary>
-        public static LocalisableString ThreadingMode => new TranslatableString(getKey(@"threading_mode"), @"Threading mode");
-
         /// <summary>
         /// "Show FPS"
         /// </summary>

osu.Game/OsuGameBase.cs

@@ -329,6 +329,21 @@ private void load(ReadableKeyCombinationProvider keyCombinationProvider, Framewo
 
             MessageFormatter.WebsiteRootUrl = endpoints.WebsiteUrl;
 
+            // Force the framework execution mode to MultiThreaded on every startup.
+            //
+            // SingleThread used to be exposed in the graphics settings, but it is incompatible
+            // with our Android Vulkan-surface readiness path: VeldridDevice / AndroidGameHost
+            // poll AndroidGameWindow.SurfaceHandle for up to 5s, and in SingleThread mode that
+            // poll runs on the same thread that publishes the surface handle, deadlocking
+            // initialisation until the timeout fires and Vulkan device creation crashes with a
+            // null function pointer (see PR history around the SDLThread/SI_TKILL crash).
+            //
+            // The same risk applies to iOS Metal layer attach (drawable surfaces are also
+            // delivered via the main loop), and on desktop SingleThread is strictly slower with
+            // no UX benefit. Upstream ppy/osu defaults to MultiThreaded; we now enforce it
+            // unconditionally so a stale `framework.ini` cannot pin a user into the broken mode.
+            frameworkConfig.SetValue(FrameworkSetting.ExecutionMode, ExecutionMode.MultiThreaded);
+
             // Initialise localisation
             frameworkLocale = frameworkConfig.GetBindable<string>(FrameworkSetting.Locale);
             frameworkLocale.BindValueChanged(_ => updateLanguage());

osu.Game/Overlays/Settings/Sections/Graphics/RendererSettings.cs

@@ -83,11 +83,6 @@ private void load(FrameworkConfigManager config, OsuConfigManager osuConfig, IDi
                     Keywords = new[] { @"fps", @"framerate" },
                 },
                 customDrawLimitItem,
-                new SettingsItemV2(new FormEnumDropdown<ExecutionMode>
-                {
-                    Caption = GraphicsSettingsStrings.ThreadingMode,
-                    Current = config.GetBindable<ExecutionMode>(FrameworkSetting.ExecutionMode)
-                }),
                 new SettingsItemV2(new FormCheckBox
                 {
                     Caption = GraphicsSettingsStrings.ShowFPS,