Merge "Fix deadlock between WMGlobal and WMS" into main (fc22d96e) · Commits · e / os / android_frameworks_base

core/java/android/view/WindowManagerGlobal.java

+20 −0

Original line number	Diff line number	Diff line
		@@ -179,9 +179,29 @@ public final class WindowManagerGlobal {
		}
		}

		/**
		* Sets {@link com.android.server.wm.WindowManagerService} for the system process.
		* <p>
		* It is needed to prevent possible deadlock. A possible scenario is:
		* In system process, WMS holds {@link com.android.server.wm.WindowManagerGlobalLock} to call
		* {@code WindowManagerGlobal} APIs and wait to lock {@code WindowManagerGlobal} itself
		* (i.e. call {@link #getWindowManagerService()} in the global lock), while
		* another component may lock {@code WindowManagerGlobal} and wait to lock
		* {@link com.android.server.wm.WindowManagerGlobalLock}(i.e call {@link #addView} in the
		* system process, which calls to {@link com.android.server.wm.WindowManagerService} API
		* directly).
		*/
		public static void setWindowManagerServiceForSystemProcess(@NonNull IWindowManager wms) {
		sWindowManagerService = wms;
		}

		@Nullable
		@UnsupportedAppUsage
		public static IWindowManager getWindowManagerService() {
		if (sWindowManagerService != null) {
		// Use WMS directly without locking WMGlobal to prevent deadlock.
		return sWindowManagerService;
		}
		synchronized (WindowManagerGlobal.class) {
		if (sWindowManagerService == null) {
		sWindowManagerService = IWindowManager.Stub.asInterface(

+5 −2

Original line number	Diff line number	Diff line
		@@ -1114,8 +1114,11 @@ public class WindowManagerService extends IWindowManager.Stub
		public static WindowManagerService main(final Context context, final InputManagerService im,
		final boolean showBootMsgs, WindowManagerPolicy policy,
		ActivityTaskManagerService atm) {
		return main(context, im, showBootMsgs, policy, atm, new DisplayWindowSettingsProvider(),
		SurfaceControl.Transaction::new, SurfaceControl.Builder::new);
		final WindowManagerService wms = main(context, im, showBootMsgs, policy, atm,
		new DisplayWindowSettingsProvider(), SurfaceControl.Transaction::new,
		SurfaceControl.Builder::new);
		WindowManagerGlobal.setWindowManagerServiceForSystemProcess(wms);
		return wms;
		}

		/**