Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932729Ab3HGMFl (ORCPT ); Wed, 7 Aug 2013 08:05:41 -0400 Received: from mail-oa0-f45.google.com ([209.85.219.45]:37891 "EHLO mail-oa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932544Ab3HGMFj convert rfc822-to-8bit (ORCPT ); Wed, 7 Aug 2013 08:05:39 -0400 MIME-Version: 1.0 In-Reply-To: <20130806154314.GA398@redhat.com> References: <20130806154314.GA398@redhat.com> Date: Wed, 7 Aug 2013 15:05:37 +0300 Message-ID: Subject: Re: [PATCH 0/1] (Was: Linux 3.11-rc4) From: Grazvydas Ignotas To: Oleg Nesterov Cc: Linus Torvalds , Felipe Contreras , Linux Kernel Mailing List , Frederic Weisbecker , Ingo Molnar , Denys Vlasenko Content-Type: text/plain; charset=ISO-8859-13 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1640 Lines: 34 On Tue, Aug 6, 2013 at 6:43 PM, Oleg Nesterov wrote: > Felipe, thanks a lot. Yes fab840f is wrong, this "bug" is already > used as a feature. > > Grazvydas, I cc'ed you because I do not really understand > set_thread_context(). It does a couple of extra PTRACE_POKEUSER's > with the "Linux 2.6.33+ needs ..." comment. It would be nice if you > can check if 3.11 still needs this, in this case we probably need > some more minor fixes in this area. > > In fact the first comment doesn't look right, when I look at 2.6.33 > it seems that POKEUSER(DR0-DR6) should be fine without POKEUSER(DR7), > but this doesn't really matter and I can be easily wrong. Anyway > this looks like a workaround to hide kernel bugs, I will appreciate > it if you can tell if wine still needs it or not. It's not that wine needs all this, it's the Windows games that use debug registers to store random values to them for their copy protection stuff. Older Linux kernels used to not care, but newer ones started validating what's written to debug registers, and those games started to break under wine. My wine commits try to sidestep these kernel restrictions/sanity checking. 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. -- Gra?vydas -- 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/