Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932680Ab3HGT0T (ORCPT ); Wed, 7 Aug 2013 15:26:19 -0400 Received: from mail-vb0-f45.google.com ([209.85.212.45]:40241 "EHLO mail-vb0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755073Ab3HGT0R (ORCPT ); Wed, 7 Aug 2013 15:26:17 -0400 MIME-Version: 1.0 In-Reply-To: References: <20130806154314.GA398@redhat.com> Date: Wed, 7 Aug 2013 12:26:16 -0700 X-Google-Sender-Auth: 58DzAWWpO8j2QLDVLYdFQ80CJIY Message-ID: Subject: Re: [PATCH 0/1] (Was: Linux 3.11-rc4) From: Linus Torvalds To: Grazvydas Ignotas Cc: Oleg Nesterov , Felipe Contreras , Linux Kernel Mailing List , Frederic Weisbecker , Ingo Molnar , Denys Vlasenko 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: 1093 Lines: 24 On Wed, Aug 7, 2013 at 5:05 AM, Grazvydas Ignotas wrote: > > Personally I'd say the kernel should not limit what's written to debug > registers. Why can't I write insane values to registers in _my_ > hardware? It's not like it's going to break the hardware or anything. It may be your hardware, but do you know what might be running on it? It's a security issue: setting debug traps on kernel code/data addresses can not only leak information, it can cause serious trouble (taking a debug trap on the first instruction of an NMI handler etc) including kernel stack corruption... You do want the kernel to give you file permission checking even though it's "your machine", don't you? Very similar thing. The fact that windows allows it is kind of irrelevant. They aren't exactly known for caring deeply. 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/