From: Rusty Russell <rusty@rustcorp.com.au>
To: Jamie Lokier <lk@tantalophile.demon.co.uk>
Cc: "Perez-Gonzalez, Inaky" <inaky.perez-gonzalez@intel.com>,
"'Mark Mielke'" <mark@mark.mielke.cc>,
linux-kernel@vger.kernel.org
Subject: Re: Users locking memory using futexes
Date: Wed, 13 Nov 2002 04:17:47 +1100 [thread overview]
Message-ID: <20021112172423.6E0322C27F@lists.samba.org> (raw)
In-Reply-To: Your message of "Tue, 12 Nov 2002 03:46:48 -0000." <20021112034648.GA11766@bjl1.asuk.net>
In message <20021112034648.GA11766@bjl1.asuk.net> you write:
> 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?
See "pipe".
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
next prev parent reply other threads:[~2002-11-12 17:17 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-11 20:28 PROT_SEM + FUTEX Perez-Gonzalez, Inaky
2002-11-11 21:46 ` Mark Mielke
2002-11-12 3:46 ` Users locking memory using futexes Jamie Lokier
2002-11-12 17:17 ` Rusty Russell [this message]
2002-11-12 18:06 ` Alan Cox
2002-11-12 18:13 ` Rusty Russell
2002-11-13 14:27 ` Alan Cox
2002-11-12 4:16 Perez-Gonzalez, Inaky
2002-11-12 5:21 ` Jamie Lokier
2002-11-12 9:11 ` Ingo Molnar
2002-11-12 17:40 ` Jamie Lokier
2002-11-12 5:56 Perez-Gonzalez, Inaky
2002-11-12 17:36 ` Jamie Lokier
2002-11-12 17:57 Perez-Gonzalez, Inaky
2002-11-12 19:17 ` Jamie Lokier
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