From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <20001118214906.D382@bug.ucw.cz> Date: Sat, 18 Nov 2000 21:49:06 +0100 From: Pavel Machek Subject: Re: KPATCH] Reserve VM for root (was: Re: Looking for better VM) References: <200011142012.VAA00150@bug.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: ; from Szabolcs Szakacsits on Thu, Nov 16, 2000 at 04:01:07PM +0100 Sender: owner-linux-mm@kvack.org Return-Path: To: Szabolcs Szakacsits Cc: Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Ingo Molnar List-ID: Hi! > > >main() { while(1) if (fork()) malloc(1); } > > >With the patch below I could ssh to the host and killall the offending > > >processes. To enable reserving VM space for root do > > what about main() { while(1) system("ftp localhost &"); } > > This. or so,ething similar should allow you to kill your machine > > even with your patch from normal user account > > This or something similar didn't kill the box [I've tried all local > DoS from Packetstorm that I could find]. Please send a working Sorry, I did not have working example, just feeling that something like that should be possible. > Note, I'm not discussing "local user can kill the box without limits", > I say Linux "deadlocks" [it starts its own autonom life and usually > your only chance is to hit the reset button] when there is continuous > VM pressure by user applications. If you think fork() kills the box That's clear bug, right? It should not deadlock, it should go to OOM-killer and kill someone. > BTW, I have a new version of the patch with that Linux behaves much > better from root's point of view when the memory is more significantly > overcommited. I'll post it if I have time [and there is interest]. There is interest. Yesterday atrey died due userland process eating all memory. Pavel PS: atrey is machine that gets my mail, so it is kind of important to me. -- I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux.eu.org/Linux-MM/