Users locking memory using futexes

From: Jamie Lokier (
Date: Mon Nov 11 2002 - 22:46:48 EST

Perez-Gonzalez, Inaky wrote:
> [...] each time you lock a futex you are pinning the containing page
> into physical memory, that would cause that if you have, for
> example, 4000 futexes locked in 4000 different pages, there is going
> to be 4 MB of memory locked in [...]

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?

-- Jamie
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This archive was generated by hypermail 2b29 : Fri Nov 15 2002 - 22:00:24 EST