Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756764AbaDLWZv (ORCPT ); Sat, 12 Apr 2014 18:25:51 -0400 Received: from terminus.zytor.com ([198.137.202.10]:57454 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755715AbaDLWZs (ORCPT ); Sat, 12 Apr 2014 18:25:48 -0400 Message-ID: <5349BD3F.6000402@zytor.com> Date: Sat, 12 Apr 2014 15:25:03 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Linus Torvalds CC: Borislav Petkov , Brian Gerst , Ingo Molnar , Linux Kernel Mailing List , Thomas Gleixner , stable , "H. Peter Anvin" Subject: Re: [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels References: <6f5f98f2-aa96-433f-9ee8-5ba216624957@email.android.com> <20140412193541.GA30697@pd.tnic> <21a22ace-fbc3-4f97-a277-9cdf4f2253eb@email.android.com> 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 04/12/2014 02:53 PM, Linus Torvalds wrote: > On Sat, Apr 12, 2014 at 12:44 PM, H. Peter Anvin wrote: >> Run a 32-bit VM. The 32-bit kernel does this right. > > I really don't think that's the answer. > > If people really run these 16-bit programs, we need to allow it. > Clearly it used to work. > > Just make the unconditional "don't allow 16-bit segments" be a sysconf entry. > Well, is there more than one user, really... that's my question. But yes, we can make it configurable, but the default should almost certainly be off. -hpa -- 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/