From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753334AbZHTF71 (ORCPT ); Thu, 20 Aug 2009 01:59:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752875AbZHTF70 (ORCPT ); Thu, 20 Aug 2009 01:59:26 -0400 Received: from cantor2.suse.de ([195.135.220.15]:42452 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814AbZHTF70 (ORCPT ); Thu, 20 Aug 2009 01:59:26 -0400 Message-ID: <4A8CE63E.9050702@suse.de> Date: Thu, 20 Aug 2009 07:59:26 +0200 From: Hannes Reinecke User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Andrew Morton Cc: Sam Ravnborg , Linux Kernel , Ingo Molnar , stable@kernel.org Subject: Re: [REGRESSION] _end symbol missing from Symbol.map References: <4A83B680.5000508@suse.de> <20090819093704.f1620baa.akpm@linux-foundation.org> In-Reply-To: <20090819093704.f1620baa.akpm@linux-foundation.org> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Thu, 13 Aug 2009 08:45:20 +0200 Hannes Reinecke wrote: > >> Hi all, >> >> with 2.6.31 'crash' on x86_64 falls flat on its face as the '_end' symbol >> is missing from the System.map file. >> >> The culprit is commit 091e52c3551d3031343df24b573b770b4c6c72b6, >> which moved the '_end' symbol into it's own section. >> Apparently this causes kallsyms to not reference it properly. >> >> So either we'd need to revert part of the patch to not >> include _end in it's own section: >> >> diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S >> index 59f31d2..1422df5 100644 >> --- a/arch/x86/kernel/vmlinux.lds.S >> +++ b/arch/x86/kernel/vmlinux.lds.S >> @@ -376,9 +376,7 @@ SECTIONS >> __brk_limit = .; >> } >> >> - .end : AT(ADDR(.end) - LOAD_OFFSET) { >> - _end = .; >> - } >> + _end = .; >> >> /* Sections to be discarded */ >> /DISCARD/ : { >> >> or someone has to fixup kallsyms. But this is far beyond my comfort zone. >> > > So System.map is part of the kernel API too? Sigh. > > Your email client replaces tabs with spaces. > I know. > The patch didn't have a signed-off-by: > I know, too. However, this is clearly a band-aid, and as such I reported it more as an RFC. One (Sam?) should really fix up kallsyms to extract the _end symbol. Hence I didn't warrant it with a Signed-off line. > I queued it up, and tagged it for -stable backporting. Unless we come > up with something better. > I was sort of hoping Sam would speak up and present some better approach ... > We might not get this into 2.6.31, in which case this fix or its > replacement will need backporting to 2.6.30.x and 2.6.31.x (IMO). > Thanks for the feedback. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Markus Rex, HRB 16746 (AG Nürnberg)