Re: [patch] futex API cleanups, futex-api-cleanup-2.5.69-A2

[Jamie Lokier]

Ingo Molnar wrote:
> > >  - start the phasing out of FUTEX_FD. This i believe is quite unclean and
> > >    unrobust, [...]
> 
> FUTEX_FD is an instant DoS, it allows the pinning of one page per file
> descriptor, per thread. With a default limit of 1024 open files per
> thread, and 256 threads (on a sane/conservative setup), this means 1 GB of
> RAM can be pinned down by a normal unprivileged user.

The correct solution [;)] is EP_FUTEX - allow a futex to be specified
as the source of an epoll event.

-- Jamie