From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754899AbaGLCJ0 (ORCPT ); Fri, 11 Jul 2014 22:09:26 -0400 Received: from terminus.zytor.com ([198.137.202.10]:42346 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753191AbaGLCJZ (ORCPT ); Fri, 11 Jul 2014 22:09:25 -0400 Message-ID: <53C098BF.6010203@zytor.com> Date: Fri, 11 Jul 2014 19:09:03 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Andy Lutomirski , Andi Kleen CC: Al Viro , X86 ML , "linux-kernel@vger.kernel.org" , Linus Torvalds Subject: Re: [PATCH 2/2] x86_64,signal: Remove 'fs' and 'gs' from sigcontext References: <20140711181212.GT18735@two.firstfloor.org> In-Reply-To: X-Enigmail-Version: 1.6 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 On 07/11/2014 11:39 AM, Andy Lutomirski wrote: > On Fri, Jul 11, 2014 at 11:12 AM, Andi Kleen wrote: >>> diff --git a/arch/x86/include/uapi/asm/sigcontext.h b/arch/x86/include/uapi/asm/sigcontext.h >>> index 076b11f..df9908b 100644 >>> --- a/arch/x86/include/uapi/asm/sigcontext.h >>> +++ b/arch/x86/include/uapi/asm/sigcontext.h >> >> I don't think renaming fields in uapi/asm is acceptable. These >> are likely used by user programs and you'll break compiles. > > Hmm. That's a fair point. On the other hand, any user code that uses > these fields explicitly may already be broken, since the current names > of these fields rather strongly imply that they do something. > > Is there any clear policy on minor API breaks in the UAPI headers that > don't affect ABI? > There really isn't, and this *definitely* a boundary case: as you state, it is very likely that anyone currently using them are doing so incorrectly, but it does induce potential source-level breakage. Linus, do you have any guidance here? -hpa