Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753023AbbHMRvg (ORCPT ); Thu, 13 Aug 2015 13:51:36 -0400 Received: from smtp17.mail.ru ([94.100.176.154]:35448 "EHLO smtp17.mail.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751559AbbHMRvf (ORCPT ); Thu, 13 Aug 2015 13:51:35 -0400 Subject: Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu To: Linus Torvalds References: <55CA90B4.2010205@list.ru> Cc: Andy Lutomirski , Linux kernel From: Stas Sergeev Message-ID: <55CCD921.4040301@list.ru> Date: Thu, 13 Aug 2015 20:51:29 +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: 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: 1843 Lines: 38 13.08.2015 18:37, Linus Torvalds пишет: > On Tue, Aug 11, 2015 at 5:17 PM, Stas Sergeev wrote: >> I realize this patch may be good to have in general, but >> breaking userspace without a single warning is a bit >> discouraging. Seems like the old "we don't break userspace" >> rule have gone. > That rule hasn't gone anywhere. > > Does a plain revert just fix everything? Because if so, that's the > right thing to do, and we can just re-visit this later. > > I don't understand why Andy and Ingo are even discussing this. What > the f*ck, guys? > > Stas, can you verify that this actually fixes it? There's two > different versions here: one that reverts *just* that one commit, and > one that reverts the fs/gs changes too. Can you test them both? Hello Linus, I verified that patch-minimal.diff is enough to fix the problem, BUT! dosemu is in fact using the .fs and .gs fields of sigcontext as a placeholders. Why the minimal patch alone helps is simply because the kernel headers installed in a system do not yet represent the newer kernel developments and have the .fs and .gs fields in. So, to allow the pre-compiled dosemu binary to run, patch-minimal is enough. To allow re-compiling it, you'd need patch.diff. Although I guess compilation is not the point, and the fact that the pre-compiled binary works, is enough. Now my PC is dying of overheat, I am struggling to even boot it. I am not sure I'll test the "really-minimal" patch, but it will unlikely to help because dosemu expects unmodified ss in a sighandler, which "really-minimal" patch doesn't seem to give. -- 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/