Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754109AbbHMWFS (ORCPT ); Thu, 13 Aug 2015 18:05:18 -0400 Received: from smtp50.i.mail.ru ([94.100.177.110]:40424 "EHLO smtp50.i.mail.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752143AbbHMWFQ (ORCPT ); Thu, 13 Aug 2015 18:05:16 -0400 Subject: Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu To: Raymond Jennings , Linus Torvalds References: <55CA90B4.2010205@list.ru> <55CCD921.4040301@list.ru> <20150813200823.GS2059@uranus> <55CD0F29.4070604@gmail.com> <55CD13A0.8060403@gmail.com> Cc: Cyrill Gorcunov , Andy Lutomirski , Pavel Emelyanov , Linux kernel From: Stas Sergeev Message-ID: <55CD1494.1070108@list.ru> Date: Fri, 14 Aug 2015 01:05:08 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <55CD13A0.8060403@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Mras: Ok Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1130 Lines: 28 14.08.2015 01:01, Raymond Jennings пишет: > > > On 08/13/15 14:46, Linus Torvalds wrote: >> On Thu, Aug 13, 2015 at 2:42 PM, Raymond Jennings >> wrote: >>> I am curious about what's supposed to happen normally on signal >>> delivery. >>> >>> Is SS a register that's supposed to be preserved like EIP/RIP and CS >>> when a >>> signal is delivered? >> What exactly does "supposed" mean? > Basically, when a process/thread receives a signal, what happens to > its registers? >> So clearly, we're not "supposed" to save/restore it. Because reality >> matters a hell of a lot more than any theoretical arguments. > So it still counts as a regression if the kernel pulls the rug out > from under someone that was relying on undocumented or buggy behavior? > You probably want to read the whole thread... Or start from here: https://lkml.org/lkml/2015/8/12/800 -- 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/