Documentation says, that "The arguments are interpreted as for debug()." But it's not true, because no matter what exc_info is passed to logging.exception(), exc_info is overwritten (kwargs['exc_info'] = 1) and later self.error is called. 
This is either documentation issue or behavior issue, because in the current implementation it's not possible to pass custom exc_info (e.g. full traceback) to logging.exception(), although documentation implies it should work the same as for info, warning, error, debug and others.