[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20110622090331.fd6a3cc7.rdunlap@xenotime.net>
Date: Wed, 22 Jun 2011 09:03:31 -0700
From: Randy Dunlap <rdunlap@...otime.net>
To: Vasiliy Kulikov <segoon@...nwall.com>
Cc: kernel-hardening@...ts.openwall.com, Andrew Morton
<akpm@...ux-foundation.org>, "Eric W. Biederman" <ebiederm@...ssion.com>,
"Serge E. Hallyn" <serge.hallyn@...onical.com>, Daniel Lezcano
<daniel.lezcano@...e.fr>, Oleg Nesterov <oleg@...hat.com>, Tejun Heo
<tj@...nel.org>, Ingo Molnar <mingo@...e.hu>, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-security-module@...r.kernel.org
Subject: Re: [RFC] ipc: introduce shm_rmid_forced sysctl
On Wed, 22 Jun 2011 19:25:14 +0400 Vasiliy Kulikov wrote:
> Signed-off-by: Vasiliy Kulikov <segoon@...nwall.com>
> ---
>
> Documentation/sysctl/kernel.txt | 22 ++++++++++
> include/linux/ipc_namespace.h | 3 +
> include/linux/shm.h | 5 ++
> ipc/ipc_sysctl.c | 33 +++++++++++++++
> ipc/shm.c | 87 +++++++++++++++++++++++++++++++++++++--
> kernel/exit.c | 1 +
> 6 files changed, 147 insertions(+), 4 deletions(-)
>
> ---
> diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
> index 5e7cb39..7a0ecfd 100644
> --- a/Documentation/sysctl/kernel.txt
> +++ b/Documentation/sysctl/kernel.txt
> @@ -62,6 +62,7 @@ show up in /proc/sys/kernel:
> - shmall
> - shmmax [ sysv ipc ]
> - shmmni
> +- shm_rmid_forced
> - stop-a [ SPARC only ]
> - sysrq ==> Documentation/sysrq.txt
> - tainted
> @@ -475,6 +476,27 @@ kernel. This value defaults to SHMMAX.
>
> ==============================================================
>
> +shm_rmid_forced:
> +
> +Linux lets you set resource limits, including on how much memory one
including how much memory one
> +process can consume, via setrlimit(2). Unfortunately, shared memory
> +segments are allowed to exist without association with any process, and
> +thus might not be counted against any resource limits. If enabled,
> +shared memory segments are automatically destroyed when their attach
> +count becomes zero after a detach or a process termination. It will
> +also destroy segments that were created, but never attached to, on exit
> +from the process. The only use left for IPC_RMID is to immediately
> +destroy an unattached segment. Of course, this breaks the way things are
> +defined, so some applications might stop working. Note that this
> +feature will do you no good unless you also configure your resource
> +limits (in particular, RLIMIT_AS and RLIMIT_NPROC). Most systems don't
> +need this.
> +
> +Note that if you change this from 0 to 1, already created segments
> +without users and with a dead originative process will be destroyed.
originating (?)
> +
> +==============================================================
> +
> softlockup_thresh:
>
> This value can be used to lower the softlockup tolerance threshold. The
---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
