From owner-freebsd-current Sat Apr 10 11: 9:54 1999 Delivered-To: freebsd-current@freebsd.org Received: from janus.syracuse.net (janus.syracuse.net [205.232.47.15]) by hub.freebsd.org (Postfix) with ESMTP id 7641B15154 for ; Sat, 10 Apr 1999 11:09:50 -0700 (PDT) (envelope-from green@unixhelp.org) Received: from localhost (green@localhost) by janus.syracuse.net (8.9.2/8.8.7) with ESMTP id OAA01047; Sat, 10 Apr 1999 14:07:28 -0400 (EDT) Date: Sat, 10 Apr 1999 14:07:27 -0400 (EDT) From: Brian Feldman X-Sender: green@janus.syracuse.net To: Dmitry Valdov Cc: freebsd-current@freebsd.org Subject: Re: DoS from local users (fwd) In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 10 Apr 1999, Dmitry Valdov wrote: > Hi! > > Once again - HOW I can limit CPU usage by *kernel* ? > Also, I've just tried set maxprocesses 5. > And it helpless. > With 5 processes limit user was able to slow down P2-450 computer. > Switching between windows in X was VERY slow. Mouse movements was slow down > too. > CPU states: 32.3% user, 0.0% nice, 67.2% system, 0.0% interrupt, 0.5% idle > > Please, just try it. If you want to preempt other tasks, make that user's tasks niced!! > > > On Sat, 10 Apr 1999, Brian Feldman wrote: > > > Date: Sat, 10 Apr 1999 09:29:19 -0400 (EDT) > > From: Brian Feldman > > To: Dmitry Valdov > > Cc: chris@calldei.com, freebsd-current@FreeBSD.ORG, > > freebsd-questions@FreeBSD.ORG > > Subject: Re: DoS from local users (fwd) > > > > On Sat, 10 Apr 1999, Dmitry Valdov wrote: > > > > > > > > > > > On Sat, 10 Apr 1999, Chris Costello wrote: > > > > > > > Date: Sat, 10 Apr 1999 02:05:33 -0500 > > > > From: Chris Costello > > > > Reply-To: chris@calldei.com > > > > To: Dmitry Valdov > > > > Cc: freebsd-current@FreeBSD.ORG, freebsd-questions@FreeBSD.ORG > > > > Subject: Re: DoS from local users (fwd) > > > > > > > > On Sat, Apr 10, 1999, Dmitry Valdov wrote: > > > > > > You typically want to set a restriction as to how many > > > > > > processes a user can spawn. This is done by editing > > > > > > /etc/login.conf and changing the user's login class, see the man > > > > > > page for 'login.conf'. > > > > > > > > > > > > > > > > I'm about CPU usage, not about many processes. > > > > > See: > > > > > CPU states: 17.8% user, 0.0% nice, 81.7% system, 0.5% interrupt, 0.0% > > > > > idle > > > > > on any (tested on P2-45) machine. > > > > > > > > > > CPU is used by SYSTEM, not by USER. So I can't restrict it with login.conf > > > > > And load average can be up to 20-40 :( > > > > > > > > > > Please don't redirect me to -questions, it's a kernel problem, not just > > > > > config. > > > > > > > > How is it a kernel problem? It's a forkbomb. It spawns many > > > > processes. You can also limit CPU usage with login.conf, I > > > > believe. > > > > > > Hmm. How I can limit CPU usage by SYSTEM? See top's output below. > > > > > > Dmitry. > > > > > > PS. I've just tried it. And I'm right - CPU usage limit can't help. > > > > > > > So? Processes that run a while go down in priority [McKusick95 I believe, THE > > book] so they are preempted easily. Look in top and see if they're all at > > the top of the list. I bet they're not! Also, you can set per-user niceness > > levels, and why are you being so liberal giving a standard LUSER 32 processes? > > This is a system administration problem. > > > > > > > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > > with "unsubscribe freebsd-current" in the body of the message > > > > > > > Brian Feldman _ __ ___ ____ ___ ___ ___ > > green@unixhelp.org _ __ ___ | _ ) __| \ > > FreeBSD: The Power to Serve! _ __ | _ \__ \ |) | > > http://www.freebsd.org _ |___/___/___/ > > > > > > Brian Feldman _ __ ___ ____ ___ ___ ___ green@unixhelp.org _ __ ___ | _ ) __| \ FreeBSD: The Power to Serve! _ __ | _ \__ \ |) | http://www.freebsd.org _ |___/___/___/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message