From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759109AbYELKBB (ORCPT ); Mon, 12 May 2008 06:01:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760799AbYELKAu (ORCPT ); Mon, 12 May 2008 06:00:50 -0400 Received: from one.firstfloor.org ([213.235.205.2]:50801 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757915AbYELKAt (ORCPT ); Mon, 12 May 2008 06:00:49 -0400 Date: Mon, 12 May 2008 12:08:09 +0200 From: Andi Kleen To: Paulo Marques Cc: Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: /proc/kallsyms broken in 2.6.26-rc1-git6 Message-ID: <20080512100809.GH31954@one.firstfloor.org> References: <20080509174148.GA22246@basil.nowhere.org> <482491D6.9030205@grupopie.com> <4824A7B6.70306@firstfloor.org> <4824AD3C.3070506@grupopie.com> <4824DB36.8000500@firstfloor.org> <4828140F.9030609@grupopie.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4828140F.9030609@grupopie.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > So, the only difference is the filter made by that "grep -v" to exclude > a few classes of symbols. > > Maybe I lost myself in that expression, but it doesn't seem like it > would be able to filter out the symbols you're seeing. Are you sure the > same symbols don't appear in System.map? They do, but that's also new. > > >They didn't use to be there and don't > >make any sense because they don't have any valid kernel addresses. > > I don't know enough about the markers infrastructure but I guess these > "addresses" are more like an "offset" into a markers structure that is > automatically produced by putting these symbols into a special section > that starts at offset 0. I don't know too much about the markers implementation either and if it's caused by then. > Well, my first suspects would be these: > > CONFIG_KPROBES=y > CONFIG_KRETPROBES=y > CONFIG_HAVE_KPROBES=y > CONFIG_HAVE_KRETPROBES=y I've always had those enabled and afaik they don't generate any magic symbols. > > > > >It's the other way round -- kallsyms changed and that change will likely > >break programs. > > I don't have the time right now to try your configuration and pinpoint > the problem, but if you can come up with a plan, like: "we need to > filter out symbols from the output of "nm" whose type is 'N'", I'll be > more than happy to provide a patch to fix it... man nm says "N" The symbol is a debugging symbol. while I'm not 100% sure what a debugging symbol is I suppose we don't need those so yes please filter those out (both out of System.map and out of kallsyms) -Andi