Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750880AbWISQpg (ORCPT ); Tue, 19 Sep 2006 12:45:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750985AbWISQpg (ORCPT ); Tue, 19 Sep 2006 12:45:36 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:1234 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1750880AbWISQpf (ORCPT ); Tue, 19 Sep 2006 12:45:35 -0400 Date: Tue, 19 Sep 2006 18:36:56 +0200 From: Ingo Molnar To: Martin Bligh Cc: Andrew Morton , "Frank Ch. Eigler" , Mathieu Desnoyers , Paul Mundt , linux-kernel , Jes Sorensen , Tom Zanussi , Richard J Moore , Michel Dagenais , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , ltt-dev@shafik.org, systemtap@sources.redhat.com, Alan Cox Subject: Re: [PATCH] Linux Kernel Markers Message-ID: <20060919163655.GA28735@elte.hu> References: <20060918234502.GA197@Krystal> <20060919081124.GA30394@elte.hu> <451008AC.6030006@google.com> <20060919154612.GU3951@redhat.com> <4510151B.5070304@google.com> <20060919093935.4ddcefc3.akpm@osdl.org> <45101DBA.7000901@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45101DBA.7000901@google.com> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 895 Lines: 28 * Martin Bligh wrote: > Andrew Morton wrote: > >On Tue, 19 Sep 2006 09:04:43 -0700 > >Martin Bligh wrote: > > > > > >>It seems like all we'd need to do > >>is "list all references to function, freeze kernel, update all > >>references, continue" > > > > > >"overwrite first 5 bytes of old function with `jmp new_function'". > > Yes, that's simple. but slower, as you have a double jump. Probably a > damned sight faster than int3 though. modern CPUs will probably even optimize that intermediate jump away in their BTB-ish caches. But in any case this would solve the function pointer problem too. Ingo - 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/