It&#x27;s hard to generalise like that.  There are lots of flavors of cap system.<p>On many hardware capability-based addressing systems it is easy to zap them by clearing the corresponding bit in the capability mask.  However, the problem then becomes how to revoke a cap from some holders and not others etc (which can be done with chains and ... turns into an interesting permission-like system ;) ...)<p>Permission-list systems have exactly the same problem too.  IIRC munmap ends up walking linked lists on Linux rather like ancient heaps.  It might have changed.