Subject: Re: [PATCH] [request for inclusion] Realtime LSM
From: Lee Revell <rlrevell@joe-job.com>
To: Arjan van de Ven <arjanv@redhat.com>
Cc: "Jack O'Quin" <joq@io.com>, Chris Wright <chrisw@osdl.org>,
       Paul Davis <paul@linuxaudiosystems.com>, Matt Mackall <mpm@selenic.com>,
       Christoph Hellwig <hch@infradead.org>, Andrew Morton <akpm@osdl.org>,
       mingo@elte.hu, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org
In-Reply-To: <20050112074906.GB5735@devserv.devel.redhat.com>
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	 <20050111150556.S10567@build.pdx.osdl.net> <87y8ezzake.fsf@sulphur.joq.us>
	 <20050112074906.GB5735@devserv.devel.redhat.com>
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Date: Wed, 12 Jan 2005 16:12:45 -0500
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On Wed, 2005-01-12 at 08:49 +0100, Arjan van de Ven wrote: 
> On Tue, Jan 11, 2005 at 07:43:29PM -0600, Jack O'Quin wrote:
> > > This is straying from the core issue...  But, Arjan's saying that an RT
> > > (non-root) task could trash the filesystem if it deadlocks the machine
> > > (because those important fs and IO threads don't run).
> > 
> > Lexicographic ambiguity: Lee and Paul are using "trash" for things
> > like installing a hidden suid root shell or co-opting sendmail into an
> > open spam relay.  Arjan just means crashing the system which forces
> > reboot to run fsck.
> 
> I actually meant data corruption.

OK, so the ability to run RT tasks implies the ability to possibly
corrupt data.  It appears that this can't be fixed until we have a real
isochronous scheduling class; for the forseeable future RT tasks will
need SCHED_FIFO and nonroot users will need to run them.

Anyway it's good to see the problem finally being taken seriously.

Lee

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