linux-kernel - Re: [PATCH] kthread: run kthreadd with max priority SCHED

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 23 Dec 2007 09:50:15 +0100
From:	Mike Galbraith <efault@....de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Jon Masters <jcm@...hat.com>, Michal Schmidt <mschmidt@...hat.com>,
	linux-kernel@...r.kernel.org,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Satoru Takeuchi <takeuchi_satoru@...fujitsu.com>
Subject: Re: [PATCH] kthread: run kthreadd with max priority SCHED_FIFO


On Sat, 2007-12-22 at 02:52 -0800, Andrew Morton wrote:
> On Sat, 22 Dec 2007 11:39:30 +0100 Mike Galbraith <efault@....de> wrote:
> 
> > 
> > On Sat, 2007-12-22 at 04:52 -0500, Jon Masters wrote:
> > 
> > > So, user tasks running with SCHED_FIFO should be able to lock a system?
> > > I guess I see both sides of this argument - yes, it's userspace at
> > > fault, but in other cases when userspace is at fault, we take action
> > > (OOM, segfault, others). Isn't this situation just another case where
> > > the kernel needs to avoid the evils of userland going awry?
> > 
> > FYI, Ingo queued the below.
> > 
> > http://lkml.org/lkml/2007/10/31/344
> > 
> 
> That's pretty different of course, but rlimit might be a suitable interface
> for implementing RLIMIT_MAX_CONTINUOUS_RT_MILLISECONDS.

I'd extend Peter's rt safety net instead: mark for forced requeue when
the soft limit is hit, or add that as an intermediate stage.  Possibly
add a demotion stage as well.  I wouldn't try to select lower priority
tasks, which RLIMIT_MAX_CONTINUOUS_RT_MILLISECONDS implies to me.

	-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/