From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267189AbUBSK7o (ORCPT ); Thu, 19 Feb 2004 05:59:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267196AbUBSK7n (ORCPT ); Thu, 19 Feb 2004 05:59:43 -0500 Received: from fw.osdl.org ([65.172.181.6]:64914 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S267189AbUBSK7i (ORCPT ); Thu, 19 Feb 2004 05:59:38 -0500 Date: Thu, 19 Feb 2004 02:59:39 -0800 From: Andrew Morton To: Nikita Danilov Cc: linux-kernel@vger.kernel.org, ltp-list@lists.sourceforge.net, error27@email.com Subject: Re: [Announce] Strace Test Message-Id: <20040219025939.3cdc52b5.akpm@osdl.org> In-Reply-To: <16436.38183.533759.45718@laputa.namesys.com> References: <20040216052257.A2C971D7214@ws3-3.us4.outblaze.com> <16436.35563.593635.277584@laputa.namesys.com> <20040219023813.2d4b0ced.akpm@osdl.org> <16436.38183.533759.45718@laputa.namesys.com> X-Mailer: Sylpheed version 0.9.4 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nikita Danilov wrote: > > Andrew Morton writes: > > Nikita Danilov wrote: > > > > > > > Strace Test uses a modified version of strace 4.5.1. > > > > Instead of printing out information about system calls, > > > > the modified version calls the syscalls with improper > > > > values. > > > > > > It immediately DoSes kernel by calling sys_sysctl() with huge nlen: > > > printk() consumes all CPU. > > > > Something like this? > > On slow console (serial kgdb) this still would be problematic. I think > printk_ratelimit() is needed. But why this loop is needed at all? It > seems strange that syscall prints its arguments instead of just > returning -EINVAL. It is kindly telling the user that the sysctl is obsolete. I'll kill it.