From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756079AbZHYT0x (ORCPT ); Tue, 25 Aug 2009 15:26:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756023AbZHYT0x (ORCPT ); Tue, 25 Aug 2009 15:26:53 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:56398 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755937AbZHYT0w (ORCPT ); Tue, 25 Aug 2009 15:26:52 -0400 Date: Tue, 25 Aug 2009 21:26:24 +0200 From: Ingo Molnar To: Ravikiran G Thirumalai Cc: Cyrill Gorcunov , Yinghai Lu , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, shai@scalex86.org, Suresh Siddha Subject: Re: [patch] x86: 2.6.31-rc7 crash due to buggy flat_phys_pkg_id Message-ID: <20090825192624.GA12763@elte.hu> References: <20090824182659.GA6842@localdomain> <4A932809.1000103@kernel.org> <20090825012632.GB6842@localdomain> <4A9372A1.9090905@kernel.org> <20090825171716.GC6456@localdomain> <20090825181500.GB3277@elte.hu> <20090825183130.GA5806@lenovo> <20090825192055.GD6456@localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090825192055.GD6456@localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ravikiran G Thirumalai wrote: > On Tue, Aug 25, 2009 at 10:31:30PM +0400, Cyrill Gorcunov wrote: > >[Ingo Molnar - Tue, Aug 25, 2009 at 08:15:00PM +0200] > >| > > > >I'm definitely not APIC expert but since I was partially involved > >letme turn in. > > > >Original commit which causes problem for vSMP seems to be due > >to cpu_has_apic bit turned off (ie due to being manually disabled > >or acpi table broken) so further read apic id will return plain > >zero (we're talking about 64 bits now). So frnakly I don't understand > >what is wrong with Ravikiran's patch. In case of apic disabled > >initial apic value will be used anyway (which is latched but > >actually may be changed, but it's not our case). > > > > Exactly my thinking. I hoped the patch I posted solves both cases -- > does not depend on local apic id for the "fix crash on certain UP configs" > case in the commit here: > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=2759c3287de27266e06f1f4e82cbd2d65f6a044c > > And fixes vsmp too. Sidenote for .32: i am somewhat worried about the spreading of various cpu_has_apic checks. We should separate it out more cleanly and provide an apic-> callback instead and avoid this ugly flaggery. Ingo