Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261606AbUDHKgV (ORCPT ); Thu, 8 Apr 2004 06:36:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261619AbUDHKgV (ORCPT ); Thu, 8 Apr 2004 06:36:21 -0400 Received: from main.gmane.org ([80.91.224.249]:27617 "EHLO main.gmane.org") by vger.kernel.org with ESMTP id S261606AbUDHKgT (ORCPT ); Thu, 8 Apr 2004 06:36:19 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: =?ISO-8859-1?Q?Sven_K=F6hler?= Subject: Re: cat /dev/hdb > /dev/null DoS Date: Thu, 08 Apr 2004 12:36:11 +0200 Message-ID: References: <20040408085518.B4607@beton.cybernet.src> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@sea.gmane.org X-Gmane-NNTP-Posting-Host: holmes.cs.upb.de User-Agent: Mozilla Thunderbird 0.5 (Windows/20040207) X-Accept-Language: en-us, en In-Reply-To: <20040408085518.B4607@beton.cybernet.src> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 669 Lines: 11 > I did cat /dev/hdb > /dev/null and after a while (5 minutes), > the system went totally unresponsive: > > 1) man top takes 3 minutes to display man page > 2) Switching between console and X takes also a couple of minutes > 3) top shows this: > > Cpu(s): 1.4% us, 1.4% sy, 0.0% ni, 0.0% id, 0.0% wa, 97.3% hi, 0.0% si i guess you have DMA enabled on /dev/hdb. I would expect, that the system is at least 50% idle - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/