Merge "[MediaProjection] Address deadlock between multiple services" into udc-qpr-dev (11246dc7) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/media/projection/MediaProjectionManagerService.java

+24 −13

Original line number	Original line	Diff line number	Diff line
	@@ -117,6 +117,10 @@ public final class MediaProjectionManagerService extends SystemService
	// WindowManagerService -> MediaProjectionManagerService -> DisplayManagerService		// WindowManagerService -> MediaProjectionManagerService -> DisplayManagerService
	// See mediaprojection.md		// See mediaprojection.md
	private final Object mLock = new Object();		private final Object mLock = new Object();
			// A handler for posting tasks that must interact with a service holding another lock,
			// especially for services that will eventually acquire the WindowManager lock.
			@NonNull private final Handler mHandler;

	private final Map<IBinder, IBinder.DeathRecipient> mDeathEaters;		private final Map<IBinder, IBinder.DeathRecipient> mDeathEaters;
	private final CallbackDelegate mCallbackDelegate;		private final CallbackDelegate mCallbackDelegate;

	@@ -145,6 +149,8 @@ public final class MediaProjectionManagerService extends SystemService
	super(context);		super(context);
	mContext = context;		mContext = context;
	mInjector = injector;		mInjector = injector;
			// Post messages on the main thread; no need for a separate thread.
			mHandler = new Handler(Looper.getMainLooper());
	mClock = injector.createClock();		mClock = injector.createClock();
	mDeathEaters = new ArrayMap<IBinder, IBinder.DeathRecipient>();		mDeathEaters = new ArrayMap<IBinder, IBinder.DeathRecipient>();
	mCallbackDelegate = new CallbackDelegate(injector.createCallbackLooper());		mCallbackDelegate = new CallbackDelegate(injector.createCallbackLooper());
	@@ -243,7 +249,9 @@ public final class MediaProjectionManagerService extends SystemService
	if (!mProjectionGrant.requiresForegroundService()) {		if (!mProjectionGrant.requiresForegroundService()) {
	return;		return;
	}		}
			}

			// Run outside the lock when calling into ActivityManagerService.
	if (mActivityManagerInternal.hasRunningForegroundService(		if (mActivityManagerInternal.hasRunningForegroundService(
	uid, ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)) {		uid, ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)) {
	// If there is any process within this UID running a FGS		// If there is any process within this UID running a FGS
	@@ -251,6 +259,7 @@ public final class MediaProjectionManagerService extends SystemService
	return;		return;
	}		}

			synchronized (mLock) {
	mProjectionGrant.stop();		mProjectionGrant.stop();
	}		}
	}		}
	@@ -867,7 +876,6 @@ public final class MediaProjectionManagerService extends SystemService
	mTargetSdkVersion = targetSdkVersion;		mTargetSdkVersion = targetSdkVersion;
	mIsPrivileged = isPrivileged;		mIsPrivileged = isPrivileged;
	mCreateTimeMs = mClock.uptimeMillis();		mCreateTimeMs = mClock.uptimeMillis();
	// TODO(b/267740338): Add unit test.
	mActivityManagerInternal.notifyMediaProjectionEvent(uid, asBinder(),		mActivityManagerInternal.notifyMediaProjectionEvent(uid, asBinder(),
	MEDIA_PROJECTION_TOKEN_EVENT_CREATED);		MEDIA_PROJECTION_TOKEN_EVENT_CREATED);
	}		}
	@@ -924,6 +932,10 @@ public final class MediaProjectionManagerService extends SystemService
	if (callback == null) {		if (callback == null) {
	throw new IllegalArgumentException("callback must not be null");		throw new IllegalArgumentException("callback must not be null");
	}		}
			// Cache result of calling into ActivityManagerService outside of the lock, to prevent
			// deadlock with WindowManagerService.
			final boolean hasFGS = mActivityManagerInternal.hasRunningForegroundService(
			uid, ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION);
	synchronized (mLock) {		synchronized (mLock) {
	if (isCurrentProjection(asBinder())) {		if (isCurrentProjection(asBinder())) {
	Slog.w(TAG, "UID " + Binder.getCallingUid()		Slog.w(TAG, "UID " + Binder.getCallingUid()
	@@ -935,9 +947,7 @@ public final class MediaProjectionManagerService extends SystemService
	}		}

	if (REQUIRE_FG_SERVICE_FOR_PROJECTION		if (REQUIRE_FG_SERVICE_FOR_PROJECTION
	&& requiresForegroundService()		&& requiresForegroundService() && !hasFGS) {
	&& !mActivityManagerInternal.hasRunningForegroundService(
	uid, ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)) {
	throw new SecurityException("Media projections require a foreground service"		throw new SecurityException("Media projections require a foreground service"
	+ " of type ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION");		+ " of type ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION");
	}		}
	@@ -1026,10 +1036,11 @@ public final class MediaProjectionManagerService extends SystemService
	mToken = null;		mToken = null;
	unregisterCallback(mCallback);		unregisterCallback(mCallback);
	mCallback = null;		mCallback = null;
	// TODO(b/267740338): Add unit test.
	mActivityManagerInternal.notifyMediaProjectionEvent(uid, asBinder(),
	MEDIA_PROJECTION_TOKEN_EVENT_DESTROYED);
	}		}
			// Run on a separate thread, to ensure no lock is held when calling into
			// ActivityManagerService.
			mHandler.post(() -> mActivityManagerInternal.notifyMediaProjectionEvent(uid, asBinder(),
			MEDIA_PROJECTION_TOKEN_EVENT_DESTROYED));
	}		}

	@Override // Binder call		@Override // Binder call

services/core/java/com/android/server/media/projection/mediaprojection.md

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -11,6 +11,11 @@ Calls must follow the below invocation order while holding locks:

	`WindowManagerService -> MediaProjectionManagerService -> DisplayManagerService`		`WindowManagerService -> MediaProjectionManagerService -> DisplayManagerService`

			`MediaProjectionManagerService` should never lock when calling into a service that may acquire
			the `WindowManagerService` global lock (for example,
			`MediaProjectionManagerService -> ActivityManagerService` may result in deadlock, since
			`ActivityManagerService -> WindowManagerService`).

	### Justification		### Justification

	`MediaProjectionManagerService` calls into `WindowManagerService` in the below cases. While handling		`MediaProjectionManagerService` calls into `WindowManagerService` in the below cases. While handling