Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933025AbbGJRjT (ORCPT ); Fri, 10 Jul 2015 13:39:19 -0400 Received: from mail-ie0-f173.google.com ([209.85.223.173]:35434 "EHLO mail-ie0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932725AbbGJRjD (ORCPT ); Fri, 10 Jul 2015 13:39:03 -0400 MIME-Version: 1.0 In-Reply-To: References: <23d4709cee2fe92c32d41b99c7a3c1823725925a.1436312944.git.luto@kernel.org> <559C8BFE.6050604@linux.intel.com> <87twtc14po.fsf@x220.int.ebiederm.org> Date: Fri, 10 Jul 2015 10:39:02 -0700 X-Google-Sender-Auth: I9wk1nKagYrMMiU862V3ujaTcGQ Message-ID: Subject: Re: [PATCH] x86/kconfig/32: Mark CONFIG_VM86 as BROKEN From: Linus Torvalds To: Andy Lutomirski Cc: "Eric W. Biederman" , Arjan van de Ven , Andy Lutomirski , "the arch/x86 maintainers" , Linux Kernel Mailing List , Oleg Nesterov , Kees Cook , Peter Zijlstra , Borislav Petkov Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1925 Lines: 41 On Fri, Jul 10, 2015 at 10:13 AM, Andy Lutomirski wrote: > > The problem is that it's *every* event. That includes this that > happen literally every time like strace. (NOHZ_FULL would count, too, > if it worked at all on 32-bit kernels.) But things like strace and auditing etc has probably never worked in the first place. So yeah, I can well imagine that vm86 isn't universally useful. And maybe it's been effectively broken in halfway modern distributions due to their insane use of auditing - which is wonderful, because it's just a stronger argument for disabling it by default. But what I'd worry about is regressions - people who actually want to upgrade kernels, and had an old machine and had an old distro, and just want to keep that working. They aren't interested in running strace on their old DOS game, or on their X server that uses it to run the video BIOS. They just want it to work. And it doesn't look "completely broken" to me for that. Put another way: I think vm86 is very much "legacy". Nobody cares about it in modern environments. That's not what we should even worry about. We shouldn't worry about new users, and we _should_ try to discourage it. But I think we should keep it working for the cases it used to work before. So no marking it "BROKEN". No calling it names just because it doesn't work in insane situations that nobody cares about. It's a legacy thing, and it probably has very few users, but I'm getting the vibe that you want to remove it or hate it just because it might not work in situations that simply don't make sense in the first place, and that it was never used for anyway. Linus -- 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/