Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765585AbXHPT2m (ORCPT ); Thu, 16 Aug 2007 15:28:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756509AbXHPT2e (ORCPT ); Thu, 16 Aug 2007 15:28:34 -0400 Received: from saraswathi.solana.com ([198.99.130.12]:51914 "EHLO saraswathi.solana.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755925AbXHPT2d (ORCPT ); Thu, 16 Aug 2007 15:28:33 -0400 Date: Thu, 16 Aug 2007 15:26:39 -0400 From: Jeff Dike To: Arjan van de Ven Cc: Andrew Morton , stable@kernel.org, LKML , uml-devel , Alberto Pires de Oliveira Neto , giedrius@su.lt Subject: Re: [PATCH] UML - Add a .note.SuSE section Message-ID: <20070816192639.GA8957@c2.user-mode-linux.org> References: <20070816162428.GA8128@c2.user-mode-linux.org> <1187281856.2663.0.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1187281856.2663.0.camel@laptopd505.fenrus.org> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2414 Lines: 65 On Thu, Aug 16, 2007 at 09:30:56AM -0700, Arjan van de Ven wrote: > this sounds like something really stupid and bad... why would the kernel > need to have a per-distro note section??? On Thu, Aug 16, 2007 at 09:39:06AM -0700, Chris Wright wrote: > Huh!? Why do we need a SuSE section? On Thu, Aug 16, 2007 at 09:54:55AM -0700, Greg KH wrote: > I agree, what did we mess up in the SuSE kernel to require such a hack? Beats the crap out of me. Drop this patch - it looks like it might just be papering over symptoms rather than fixing the real problem - see below. What I do know is that current UML doesn't run when built on a SuSE host, the UML commit which caused it to break is c35e584c087381aaa5f1ed40a28b978535c18fb2 http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=c35e584c087381aaa5f1ed40a28b978535c18fb2;hp=a5bd1786fb30abe663b904f6d79bba413e9ba883 and the difference between a working UML binary and a broken one is this: + 1 .note.ABI-tag 00000020 0000000060000254 0000000060000254 00000254 2**2 + CONTENTS, ALLOC, LOAD, READONLY, DATA + 2 .note.SuSE 00000018 0000000060000274 0000000060000274 00000274 2**2 + CONTENTS, ALLOC, LOAD, READONLY, DATA and the .note.SuSE section makes the difference. Looking into it a bit further, the contents of the section are: objdump --section=.note.SuSE -s uml8796-linux-good uml8796-linux-good: file format elf64-x86-64 Contents of section .note.SuSE: 60000274 05000000 04000000 53755345 53755345 ........SuSESuSE 60000284 00000000 01000a02 ........ which seems kind of pointless, but also harmless. The crash is in this section: __uml_setup_start = .; .uml.setup.init : { *(.uml.setup.init) } __uml_setup_end = .; with &__uml_setup_start being 8 bytes before the start of the first 16-byte structure in .uml.setup.init, so the structures are misaligned wrt the start symbol. I don't see any connection between the presence of a section at the start of the binary and this misalignment, so the patch is probably wrong. Jeff -- Work email - jdike at linux dot intel dot com - 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/