Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934305AbcLBOhG (ORCPT ); Fri, 2 Dec 2016 09:37:06 -0500 Received: from out5-smtp.messagingengine.com ([66.111.4.29]:60216 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756968AbcLBOgq (ORCPT ); Fri, 2 Dec 2016 09:36:46 -0500 X-ME-Sender: X-Sasl-enc: xoo66q9QznHxjzEnNbf7YlYF7iJxmmKdUpoA6vR/4xIP 1480689404 Subject: Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm To: Michal Marek , Nicholas Piggin , Ben Hutchings References: <20161129131922.GA31466@angband.pl> <20161129135118.24696-1-kilobyte@angband.pl> <30bb2db4-47bd-0c35-8328-ef032b551f06@suse.com> <20161129195721.GI2697@decadent.org.uk> <20161201051852.28dc335f@roar.ozlabs.ibm.com> <1480541581.16599.78.camel@decadent.org.uk> <20161201125545.406d092c@roar.ozlabs.ibm.com> <1480559754.16599.92.camel@decadent.org.uk> <20161201143928.07a08348@roar.ozlabs.ibm.com> <6e8cf20b-2d2f-ba1f-e02c-c757d5a25db7@suse.com> Cc: Linus Torvalds , Adam Borowski , Greg Kroah-Hartman , Linux Kbuild mailing list , Debian kernel maintainers , "linux-arch@vger.kernel.org" , Arnd Bergmann , Ingo Molnar , Linux Kernel Mailing List , Dodji Seketeli From: Hannes Frederic Sowa Message-ID: Date: Fri, 2 Dec 2016 15:36:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <6e8cf20b-2d2f-ba1f-e02c-c757d5a25db7@suse.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1400 Lines: 32 On 01.12.2016 17:12, Michal Marek wrote: > On 2016-12-01 04:39, Nicholas Piggin wrote: >> On Thu, 01 Dec 2016 02:35:54 +0000 >> Ben Hutchings wrote: >>> As I understand it, genksyms incorporates the definitions of a >>> function's parameter and return types - not just their names - and all >>> the types they refer to, recursively. So a structure size change >>> should change the version of all functions where the function and its >>> caller pass that structure between them, however indirectly. It finds >>> such indirect ABI breakage for me fairly regularly, though of course I >>> don't know that it finds everything. >> >> It is only the type name. >> >> Not only that but even if you did extend it further to structure type >> arrangement then you still have to deal with other structures followed >> via pointers. Or (rarer but not unheard of): >> >> - changes to structures without changes of the types of their members >> - changes to arguments without changes of their type > > This is already covered by genksyms. Try make V=1 with > CONFIG_MODVERSIONS=y and add the -D option to one of the genksyms > command. I wanted to paste the expanded signature for > register_filesystem() as an example, but vger would probably drop the > mail for being too big :). It is easier to just use e.g. `make net/core/dev.symtypes` and look at the generated file. Bye, Hannes