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Commit 1422e557 authored by Naomi Musgrave's avatar Naomi Musgrave Committed by Automerger Merge Worker
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Merge "[MediaProjection] Address deadlock between multiple services" into... 

Merge "[MediaProjection] Address deadlock between multiple services" into udc-dev am: 607bd36f am: 91660e8b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24150805



Change-Id: If80c9df523bd480f6b55607d07f8a2695bcf062b
Signed-off-by: default avatarAutomerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
parents 8ad856ac 91660e8b

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

+27 −14
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();

        mCallbackDelegate = new CallbackDelegate();
@@ -238,7 +244,9 @@ 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
@@ -246,9 +254,12 @@ public final class MediaProjectionManagerService extends SystemService 
            return;

            return;

        }

        }





        synchronized (mLock) {

            if (mProjectionGrant != null) {

                mProjectionGrant.stop();

                mProjectionGrant.stop();

            }

            }

        }

        }

    }





    private void startProjectionLocked(final MediaProjection projection) {

    private void startProjectionLocked(final MediaProjection projection) {

        if (mProjectionGrant != null) {

        if (mProjectionGrant != null) {
@@ -854,7 +865,6 @@ 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);

        }

        }
@@ -911,6 +921,10 @@ 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()
@@ -922,9 +936,7 @@ 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");

                }

                }
@@ -1013,10 +1025,11 @@ 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