From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753552AbbIBJdh (ORCPT ); Wed, 2 Sep 2015 05:33:37 -0400 Received: from smtp47.i.mail.ru ([94.100.177.107]:45814 "EHLO smtp47.i.mail.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752778AbbIBJdf (ORCPT ); Wed, 2 Sep 2015 05:33:35 -0400 To: Andy Lutomirski Cc: Ingo Molnar , Linus Torvalds , Linux kernel , "Andrew Bird (Sphere Systems)" From: Stas Sergeev Subject: stop breaking dosemu (Re: x86/kconfig/32: Rename CONFIG_VM86 and default it to 'n') Message-ID: <55E6C36F.6080309@list.ru> Date: Wed, 2 Sep 2015 12:37:51 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Mras: Ok Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org https://lkml.org/lkml/2015/7/21/208 Guys, you gonna be kidding. Is this a new trend of breaking dosemu, or what? > VM86 is entirely broken if ptrace, syscall auditing, or > NOHZ_FULL is in use. The code is a big undocumented mess, it's > a real PITA to test, and it looks like a big chunk of vm86_32.c It is a CPU feature that kernel should support, and always did without any problems. If it started to have problems because of your actions, then you can as well fix your code. > No one should be using it anyway. Use DOSBOX or KVM instead. Have you done the benchmarks between dosbox and dosemu before saying that? Please do, thanks. (don't forget to include dosemu2 in your benchmarks too, as it outperforms both) > Let's accelerate its slow death. > + Enabling this option adds considerable attack surface to the > + kernel and slows down system calls and exception handling. Yes, I realize that threatening people with the "considerable attack surface" is a good way to "accelerate its slow death", but please care to explain that attack surface, thankyou.