From owner-freebsd-hackers Wed Mar 22 14: 3: 7 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from fw.wintelcom.net (ns1.wintelcom.net [209.1.153.20]) by hub.freebsd.org (Postfix) with ESMTP id D7CE937C29B for ; Wed, 22 Mar 2000 14:03:02 -0800 (PST) (envelope-from bright@fw.wintelcom.net) Received: (from bright@localhost) by fw.wintelcom.net (8.10.0/8.10.0) id e2MMQNq13691; Wed, 22 Mar 2000 14:26:23 -0800 (PST) Date: Wed, 22 Mar 2000 14:26:23 -0800 From: Alfred Perlstein To: kc5vdj@swbell.net 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: <20000322142623.R7305@fw.wintelcom.net> References: <20000322102407.K7305@fw.wintelcom.net> <200003222155.PAA35282@ppp-207-193-186-239.kscymo.swbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i In-Reply-To: <200003222155.PAA35282@ppp-207-193-186-239.kscymo.swbell.net>; from jbryant@ppp-207-193-186-239.kscymo.swbell.net on Wed, Mar 22, 2000 at 03:55:17PM -0600 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG * Jim Bryant [000322 14:19] wrote: > 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. True. > > #!/bin/csh > /usr/games/primes 1 4294967295 >&/dev/null& .... > /usr/games/primes 1 4294967295 >&/dev/null& > # etc, ... > # > # [get the idea?] why are you 'scripting' in csh? eww. No i don't get the idea, login.conf in FreeBSD is able to limit a user to a maximum amount of processes, I think even cputime limitations work but I haven't tried them. Yes, and one shouldn't give accounts out to irresponcible/thoughtless people. 'rmuser' is your friend. -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message