Re: Users locking memory using futexes

[Alan Cox]

On Tue, 2002-11-12 at 17:17, Rusty Russell wrote:
> > Ouch!  It looks to me like userspace can use FUTEX_FD to lock many
> > pages of memory, achieving the same as mlock() but without the
> > resource checks.
> > 
> > Denial of service attack?
> 
> See "pipe".

Thats not an excuse. If the futex stuff allows arbitary memory locking
and it isnt properly accounted then its a bug, with the added problem
that its easier to have nasty accidents with than pipes.

We have a per user object nowdays so accounting per user locked memory
looks rather doable both for mlock, pipe, af_unix socket and for other
things