From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6AC89C10F13 for ; Tue, 16 Apr 2019 19:09:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3104920663 for ; Tue, 16 Apr 2019 19:09:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729811AbfDPTJS (ORCPT ); Tue, 16 Apr 2019 15:09:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:33002 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727136AbfDPTJR (ORCPT ); Tue, 16 Apr 2019 15:09:17 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 34599AF9A; Tue, 16 Apr 2019 19:09:16 +0000 (UTC) Date: Tue, 16 Apr 2019 21:09:15 +0200 (CEST) From: Miroslav Benes To: Joe Lawrence cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, linux-kbuild@vger.kernel.org, Jessica Yu , Jiri Kosina , Joao Moreira , Josh Poimboeuf , Konstantin Khlebnikov , Masahiro Yamada , Michael Matz , Nicolai Stange , Petr Mladek Subject: Re: [PATCH v3 0/9] klp-convert livepatch build tooling In-Reply-To: <452e0cc5-ea9b-1638-3557-17e12671e21e@redhat.com> Message-ID: References: <20190410155058.9437-1-joe.lawrence@redhat.com> <452e0cc5-ea9b-1638-3557-17e12671e21e@redhat.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Apr 2019, Joe Lawrence wrote: > On 4/10/19 11:50 AM, Joe Lawrence wrote: > > Hi folks, > > > > This is the third installment of the klp-convert tool for generating and > > processing livepatch symbols for livepatch module builds. For those > > following along at home, archive links to previous versions: > > > > RFC: > > https://lore.kernel.org/lkml/cover.1477578530.git.jpoimboe@redhat.com/ > > v2: > > https://lore.kernel.org/lkml/f52d29f7-7d1b-ad3d-050b-a9fa8878faf2@redhat.com/ > > > > (Note that I don't see v2 archived at lore, but that is a link to the > > most recent subthread that lore did catch.) > > > > > > Livepatches may use symbols which are not contained in its own scope, > > and, because of that, may end up compiled with relocations that will > > only be resolved during module load. Yet, when the referenced symbols are > > not exported, solving this relocation requires information on the object > > that holds the symbol (either vmlinux or modules) and its position inside > > the object, as an object may contain multiple symbols with the same name. > > Providing such information must be done accordingly to what is specified > > in Documentation/livepatch/module-elf-format.txt. > > Hi Miroslav, > > I noticed that some binutils programs like gdb, objdump, etc. don't like the > .ko kernel objects that we're generating from this patchset, specifically > those with the additional '.klp.rela...text' livepatch symbol relocation > sections. > > For reference, I opened a new bugzilla with more details here: > https://sourceware.org/bugzilla/show_bug.cgi?id=24456 Another great catch. > And was about to ping the binutils mailing list about the assertion that is > tripping in bfd/elf.c. The thought occurred to me that you guys might already > be carrying a patch to workaround this issue? No, unfortunately we don't. At least I don't know about anything and a quick test on openSUSE Leap 15.0 confirms it (objdump -D gives "bad value"). Thanks Miroslav