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Merge "[MediaProjection] Address deadlock between multiple services" into udc-dev

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This commit is contained in:
Naomi Musgrave
2023-08-03 09:39:07 +00:00
committed by Android (Google) Code Review
parent cbfe13a3dd 0003ce7a48
commit 607bd36fba
2 changed files with 32 additions and 14 deletions
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41
services/core/java/com/android/server/media/projection/MediaProjectionManagerService.java
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@@ -117,6 +117,10 @@ public final class MediaProjectionManagerService extends SystemService
// WindowManagerService -> MediaProjectionManagerService -> DisplayManagerService
// See mediaprojection.md
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 CallbackDelegate mCallbackDelegate;
@@ -145,6 +149,8 @@ public final class MediaProjectionManagerService extends SystemService
super(context);
mContext = context;
mInjector = injector;
// Post messages on the main thread; no need for a separate thread.
mHandler = new Handler(Looper.getMainLooper());
mClock = injector.createClock();
mDeathEaters = new ArrayMap<IBinder, IBinder.DeathRecipient>();
mCallbackDelegate = new CallbackDelegate();
@@ -238,15 +244,20 @@ public final class MediaProjectionManagerService extends SystemService
if (!mProjectionGrant.requiresForegroundService()) {
return;
}
}
if (mActivityManagerInternal.hasRunningForegroundService(
uid, ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)) {
// If there is any process within this UID running a FGS
// with the mediaProjection type, that's Okay.
return;
// Run outside the lock when calling into ActivityManagerService.
if (mActivityManagerInternal.hasRunningForegroundService(
uid, ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)) {
// If there is any process within this UID running a FGS
// with the mediaProjection type, that's Okay.
return;
}
synchronized (mLock) {
if (mProjectionGrant != null) {
mProjectionGrant.stop();
}
mProjectionGrant.stop();
}
}
@@ -854,7 +865,6 @@ public final class MediaProjectionManagerService extends SystemService
mTargetSdkVersion = targetSdkVersion;
mIsPrivileged = isPrivileged;
mCreateTimeMs = mClock.uptimeMillis();
// TODO(b/267740338): Add unit test.
mActivityManagerInternal.notifyMediaProjectionEvent(uid, asBinder(),
MEDIA_PROJECTION_TOKEN_EVENT_CREATED);
}
@@ -911,6 +921,10 @@ public final class MediaProjectionManagerService extends SystemService
if (callback == 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) {
if (isCurrentProjection(asBinder())) {
Slog.w(TAG, "UID " + Binder.getCallingUid()
@@ -922,9 +936,7 @@ public final class MediaProjectionManagerService extends SystemService
}
if (REQUIRE_FG_SERVICE_FOR_PROJECTION
&& requiresForegroundService()
&& !mActivityManagerInternal.hasRunningForegroundService(
uid, ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION)) {
&& requiresForegroundService() && !hasFGS) {
throw new SecurityException("Media projections require a foreground service"
+ " of type ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PROJECTION");
}
@@ -1013,10 +1025,11 @@ public final class MediaProjectionManagerService extends SystemService
mToken = null;
unregisterCallback(mCallback);
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

5
services/core/java/com/android/server/media/projection/mediaprojection.md
View File

@@ -11,6 +11,11 @@ Calls must follow the below invocation order while holding locks:
`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
`MediaProjectionManagerService` calls into `WindowManagerService` in the below cases. While handling