Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753417AbeAFUnE (ORCPT + 1 other); Sat, 6 Jan 2018 15:43:04 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:38597 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752213AbeAFUnB (ORCPT ); Sat, 6 Jan 2018 15:43:01 -0500 Date: Sat, 6 Jan 2018 21:42:29 +0100 From: Willy Tarreau To: Alan Cox Cc: Alexei Starovoitov , Linus Torvalds , Dan Williams , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Andi Kleen , Arnd Bergmann , Greg Kroah-Hartman , Peter Zijlstra , netdev@vger.kernel.org, Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH 06/18] x86, barrier: stop speculation for failed access_ok Message-ID: <20180106204229.GD9075@1wt.eu> References: <151520099201.32271.4677179499894422956.stgit@dwillia2-desk3.amr.corp.intel.com> <151520102670.32271.8447983009852138826.stgit@dwillia2-desk3.amr.corp.intel.com> <20180106123242.77f4d860@alans-desktop> <20180106181331.mmrqwwbu2jcjj2si@ast-mbp> <20180106183859.1ad9ae37@alans-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180106183859.1ad9ae37@alans-desktop> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Sat, Jan 06, 2018 at 06:38:59PM +0000, Alan Cox wrote: > Normally people who propose security fixes don't have to argue about the > fact they added 30 clocks to avoid your box being 0wned. In fact it depends, because if a fix makes the system unusable for its initial purpose, this fix will simply not be deployed at all, which is the worst that can happen. Especially when it cannot be disabled by config and people stop updating their systems to stay on the last "known good" version. Fortunately in Linux we often have the choice so that users rarely have a valid reason for not upgrading! Willy