Merge "Revert "Avoid wm<->am deadlock when checking uri permission"" into... (fcab2f03) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/am/ActivityManagerService.java

+20 −32

Original line number	Original line	Diff line number	Diff line
	@@ -337,7 +337,6 @@ import com.android.internal.util.Preconditions;
	import com.android.internal.util.function.HexFunction;		import com.android.internal.util.function.HexFunction;
	import com.android.internal.util.function.QuadFunction;		import com.android.internal.util.function.QuadFunction;
	import com.android.internal.util.function.TriFunction;		import com.android.internal.util.function.TriFunction;
	import com.android.internal.util.function.pooled.PooledLambda;
	import com.android.server.AlarmManagerInternal;		import com.android.server.AlarmManagerInternal;
	import com.android.server.AttributeCache;		import com.android.server.AttributeCache;
	import com.android.server.DeviceIdleInternal;		import com.android.server.DeviceIdleInternal;
	@@ -18832,39 +18831,28 @@ public class ActivityManagerService extends IActivityManager.Stub
	@Override		@Override
	public int checkContentProviderUriPermission(Uri uri, int userId,		public int checkContentProviderUriPermission(Uri uri, int userId,
	int callingUid, int modeFlags) {		int callingUid, int modeFlags) {
	final Object wmLock = mActivityTaskManager.getGlobalLock();		// We can find ourselves needing to check Uri permissions while
	if (Thread.currentThread().holdsLock(wmLock)		// already holding the WM lock, which means reaching back here for
	&& !Thread.currentThread().holdsLock(ActivityManagerService.this)) {		// the AM lock would cause an inversion. The WM team has requested
	// We can find ourselves needing to check Uri permissions while already holding the		// that we use the strategy below instead of shifting where Uri
	// WM lock, which means reaching back here for the AM lock would cause an inversion.		// grants are calculated.
	// The WM team has requested that we use the strategy below instead of shifting
	// where Uri grants are calculated.		// Since we could also arrive here while holding the AM lock, we
	synchronized (wmLock) {		// can't always delegate the call through the handler, and we need
	final int[] result = new int[1];		// to delicately dance between the deadlocks.
	final Message msg = PooledLambda.obtainMessage(		if (Thread.currentThread().holdsLock(ActivityManagerService.this)) {
	LocalService::checkContentProviderUriPermission,
	this, uri, userId, callingUid, modeFlags, wmLock, result);
	mHandler.sendMessage(msg);
	try {
	wmLock.wait();
	} catch (InterruptedException ignore) {

	}
	return result[0];
	}
	} else {
	return ActivityManagerService.this.checkContentProviderUriPermission(uri,		return ActivityManagerService.this.checkContentProviderUriPermission(uri,
	userId, callingUid, modeFlags);		userId, callingUid, modeFlags);
	}		} else {
	}		final CompletableFuture<Integer> res = new CompletableFuture<>();
			mHandler.post(() -> {
	void checkContentProviderUriPermission(		res.complete(ActivityManagerService.this.checkContentProviderUriPermission(uri,
	Uri uri, int userId, int callingUid, int modeFlags, Object wmLock, int[] result) {		userId, callingUid, modeFlags));
	synchronized (ActivityManagerService.this) {		});
	synchronized (wmLock) {		try {
	result[0] = ActivityManagerService.this.checkContentProviderUriPermission(		return res.get();
	uri, userId, callingUid, modeFlags);		} catch (InterruptedException \| ExecutionException e) {
	wmLock.notify();		throw new RuntimeException(e);
	}		}
	}		}
	}		}