From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754403AbXD1Wpn (ORCPT ); Sat, 28 Apr 2007 18:45:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754394AbXD1Wpn (ORCPT ); Sat, 28 Apr 2007 18:45:43 -0400 Received: from [70.254.190.220] ([70.254.190.220]:46449 "EHLO server.willdawg" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1754367AbXD1WpE (ORCPT ); Sat, 28 Apr 2007 18:45:04 -0400 Date: Sat, 28 Apr 2007 22:45:03 +0000 (GMT) From: William Heimbigner X-X-Sender: icxcnika@server.thyself To: Lee Revell cc: tglx@linutronix.de, matthieu castet , Linux Kernel list , Ingo Molnar , Andrew Morton Subject: Re: High Resolution Timer DOS In-Reply-To: <75b66ecd0704281537s54134967ybc3ddef0b87b6bf5@mail.gmail.com> Message-ID: References: <4633C269.9050806@free.fr> <1177798389.7646.320.camel@localhost.localdomain> <75b66ecd0704281537s54134967ybc3ddef0b87b6bf5@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 28 Apr 2007, Lee Revell wrote: > On 4/28/07, Thomas Gleixner wrote: >> >> Well, it is not really a DoS. The rescheduling of the process is limited >> by the scheduler and the available CPU time (depending on the number of >> runnable tasks in the system). > > Shouldn't an unprivileged process be rate limited somehow to avoid > flooding the machine with interrupts? We restrict nonroot users from > setting the RTC interrupt rate higher than 64Hz for a similar reason > (granted, this limit dates back to the 486 days and should probably be > increased to 1024 Hz). Isn't that what /etc/security/limits.conf is for? Just limit the CPU usage. > Root and SCHED_FIFO tasks could be exempt from rate limiting, to avoid > the need to introduce a new rlimit which would take years for > userspace to catch up to. > > Lee William Heimbigner icxcnika@mar.tar.cc