Re: low priority soft RT?

Stephen C. Tweedie (sct@redhat.com)
Fri, 23 Jul 1999 17:21:03 +0100 (BST)


Hi,

On Thu, 22 Jul 1999 21:39:48 +0200 (CEST), Rik van Riel
<riel@nl.linux.org> said:

> I have made a fairly substantial SCHED_IDLE patch, but due to
> the (never resolved) deadlock issues I haven't submitted it.

Yes, it really is a loaded gun. A large SCHED_IDLE process can consume
arbitrary system resources, and if there is any single cpu-bound process
preventing it from being scheduled, you won't even be able to kill -9
the SCHED_IDLE task (the kill signal isn't delivered until the task is
next scheduled).

It is much more dangerous than it first appears, and the DoS attacks
look really nasty.

--Stephen

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