From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Perez-Gonzalez, Inaky" <inaky.perez-gonzalez@intel.com>,
"'Mark Mielke'" <mark@mark.mielke.cc>,
linux-kernel@vger.kernel.org
Subject: Users locking memory using futexes
Date: Tue, 12 Nov 2002 03:46:48 +0000 [thread overview]
Message-ID: <20021112034648.GA11766@bjl1.asuk.net> (raw)
In-Reply-To: <A46BBDB345A7D5118EC90002A5072C7806CAC917@orsmsx116.jf.intel.com>
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
next prev parent reply other threads:[~2002-11-12 3:40 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 ` Jamie Lokier [this message]
2002-11-12 17:17 ` Users locking memory using futexes Rusty Russell
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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