Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757261AbcLAS0M (ORCPT ); Thu, 1 Dec 2016 13:26:12 -0500 Received: from mail-io0-f195.google.com ([209.85.223.195]:33929 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756656AbcLAS0J (ORCPT ); Thu, 1 Dec 2016 13:26:09 -0500 MIME-Version: 1.0 In-Reply-To: <2899250.iZaPagXLk8@wuerfel> References: <20161129131922.GA31466@angband.pl> <2899250.iZaPagXLk8@wuerfel> From: Linus Torvalds Date: Thu, 1 Dec 2016 10:26:07 -0800 X-Google-Sender-Auth: cJndm7sUMQHgdsYRrEvAUssDWs4 Message-ID: Subject: Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm To: Arnd Bergmann Cc: Adam Borowski , Greg Kroah-Hartman , Linux Kbuild mailing list , Michal Marek , Ben Hutchings , Debian kernel maintainers , "linux-arch@vger.kernel.org" , Ingo Molnar , Nicholas Piggin , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1586 Lines: 25 On Thu, Dec 1, 2016 at 5:58 AM, Arnd Bergmann wrote: > > WARNING: EXPORT symbol "mcount" [arch/x86/entry/built-in.ko] version generation failed, symbol will not be versioned. > WARNING: EXPORT symbol "mcount" [arch/x86/built-in.ko] version generation failed, symbol will not be versioned. > WARNING: EXPORT symbol "cmpxchg8b_emu" [vmlinux] version generation failed, symbol will not be versioned. > WARNING: EXPORT symbol "empty_zero_page" [vmlinux] version generation failed, symbol will not be versioned. > WARNING: EXPORT symbol "mcount" [vmlinux] version generation failed, symbol will not be versioned. > WARNING: EXPORT symbol "cmpxchg8b_emu" [vmlinux] version generation failed, symbol will not be versioned. > WARNING: EXPORT symbol "empty_zero_page" [vmlinux] version generation failed, symbol will not be versioned. > WARNING: EXPORT symbol "mcount" [vmlinux] version generation failed, symbol will not be versioned. > > Out of 12 randconfig builds that had CONFIG_MODVERSIONS enabled, all 12 > had this problem, though not always with all the symbols. Well, the good news is that pretty fundamentally, if it's just the asm symbls, those really don't have ABI's that change (or if they change, it's such a fundamental change that everything else will likely have changed too and we don't need to worry about one asm symbol crc - the change will be caught by other symbols). So I think the whole "we don't really care" approach should work fine. The "let's make every symbol always be versioned" may just be too much pain for no real gain. Linus