Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756622AbZJ2TTH (ORCPT ); Thu, 29 Oct 2009 15:19:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756586AbZJ2TTG (ORCPT ); Thu, 29 Oct 2009 15:19:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22789 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756421AbZJ2TTF (ORCPT ); Thu, 29 Oct 2009 15:19:05 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Ingo Molnar X-Fcc: ~/Mail/linus Cc: Masami Hiramatsu , Arnaldo Carvalho de Melo , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , lkml , Steven Rostedt , Jim Keniston , Ananth N Mavinakayanahalli , Christoph Hellwig , "Frank Ch. Eigler" , "H. Peter Anvin" , Jason Baron , "K.Prasad" , Peter Zijlstra , Srikar Dronamraju , systemtap , DLE Subject: Re: [PATCH -tip perf/probes 00/10] x86 insn decoder bugfixes In-Reply-To: Ingo Molnar's message of Thursday, 29 October 2009 09:53:48 +0100 <20091029085348.GD26970@elte.hu> References: <20091027204156.30545.96425.stgit@harusame> <20091029085348.GD26970@elte.hu> X-Shopping-List: (1) Urgent digressions (2) Allegorical bits (3) Lucky hamster-lips Message-Id: <20091029191801.CADC3538@magilla.sf.frob.com> Date: Thu, 29 Oct 2009 12:18:01 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1055 Lines: 23 > Thirdly, i think we should expose the build-id of the kernel and the > path to the vmlinux (and modules) via /proc/build-id or so. That way > tooling can find the vmlinux file and can validate that it matches the > kernel's signature. (maybe include a file date as well - that's a faster > check than a full build-id checksum, especially for large kernels) You seem to be confused about what build IDs are. There is no "checksum validation". Once the bits are stored there is no calculation ever done again, only exact comparison with an expected build ID bitstring. The size of an object file is immaterial. As Frank mentioned, the kernel's and modules' allocated ELF notes (and thus build IDs) are already exposed in /sys. Tools like "eu-unstrip -nk" use this information today. Thanks, Roland -- 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/