Add null check in BackupManagerService$PerformBackupTask.handleCancel()

                    return;

                }

                mCancelAll = cancelAll;

                // Whoops, the current agent timed out running doBackup().  Tidy up and restage

                // it for the next time we run a backup pass.

                // !!! TODO: keep track of failure counts per agent, and blacklist those which

                // fail repeatedly (i.e. have proved themselves to be buggy).

                Slog.e(TAG, "Cancel backing up " + mCurrentPackage.packageName);

                EventLog.writeEvent(EventLogTags.BACKUP_AGENT_FAILURE, mCurrentPackage.packageName);

                final String logPackageName = (mCurrentPackage != null)

                        ? mCurrentPackage.packageName

                        : "no_package_yet";

                Slog.i(TAG, "Cancel backing up " + logPackageName);

                EventLog.writeEvent(EventLogTags.BACKUP_AGENT_FAILURE, logPackageName);

                addBackupTrace("cancel of " + logPackageName + ", cancelAll=" + cancelAll);

                mMonitor = monitorEvent(mMonitor,

                        BackupManagerMonitor.LOG_EVENT_ID_KEY_VALUE_BACKUP_CANCEL,

                        mCurrentPackage, BackupManagerMonitor.LOG_EVENT_CATEGORY_AGENT,

                        putMonitoringExtra(null, BackupManagerMonitor.EXTRA_LOG_CANCEL_ALL,

                                mCancelAll));

                addBackupTrace(

                        "cancel of " + mCurrentPackage.packageName + ", cancelAll=" + cancelAll);

                errorCleanup();

                if (!cancelAll) {

                    // The current agent either timed out or was cancelled running doBackup().

                    // Restage it for the next time we run a backup pass.

                    // !!! TODO: keep track of failure counts per agent, and blacklist those which

                    // fail repeatedly (i.e. have proved themselves to be buggy).

                    executeNextState(

                            mQueue.isEmpty() ? BackupState.FINAL : BackupState.RUNNING_QUEUE);

                    dataChangedImpl(mCurrentPackage.packageName);