From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752745Ab2LQNLY (ORCPT ); Mon, 17 Dec 2012 08:11:24 -0500 Received: from mailgw1.uni-kl.de ([131.246.120.220]:59137 "EHLO mailgw1.uni-kl.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752125Ab2LQNLX (ORCPT ); Mon, 17 Dec 2012 08:11:23 -0500 Message-ID: <50CF19EA.3070203@itwm.fraunhofer.de> Date: Mon, 17 Dec 2012 14:11:06 +0100 From: Bernd Schubert User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Borislav Petkov , Yinghai Lu , Ingo Molnar , linux-kernel@vger.kernel.org, Weidong Han , David Woodhouse , sbsiddha@gmail.com Subject: Re: [regression] 3.7 ends in APIC panic References: <50CB3EAB.309@itwm.fraunhofer.de> <50CE0C82.20708@itwm.fraunhofer.de> <50CE12EB.1050804@itwm.fraunhofer.de> <20121216191347.GB14678@liondog.tnic> <50CE24FE.3030409@itwm.fraunhofer.de> <20121216203913.GB14643@liondog.tnic> <50CEE736.8020000@itwm.fraunhofer.de> <20121217100014.GA31866@liondog.tnic> In-Reply-To: <20121217100014.GA31866@liondog.tnic> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ITWM-CharSet: UTF-8 X-ITWM-Scanned-By: mail2.itwm.fhg.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/17/2012 11:00 AM, Borislav Petkov wrote: > + Suresh. > > On Mon, Dec 17, 2012 at 10:34:46AM +0100, Bernd Schubert wrote: >> On 12/16/2012 09:39 PM, Borislav Petkov wrote: >>> On Sun, Dec 16, 2012 at 08:46:06PM +0100, Bernd Schubert wrote: >>>> Hmm, I read it the other way around - x2apic depends on interrupt >>>> remapping, but interrupt remapping can be used without x2apic. >>> >>> Ok, you're right. X2APIC should depend on IRQ_REMAP: >>> https://lwn.net/Articles/289881/ >>> >>>> The help text of CONFIG_IRQ_REMAP also says "x2APIC enhancements or to >>>> support platforms with CPU's having > 8 bit APIC ID, say Y." I guess >>>> may CPU has the latter? >>> >>> I think it is what Yinghai said - you obviously need x2apic kernel >>> support if you have IRQ_REMAP on. >>> >>>> Can the kernel panic a bit improved to help user to understand what >>>> needs to be enabled? >>> >>> Well, your kernel enables IRQ_REMAP properly: >>> >>> [ 0.031115] Enabled IRQ remapping in x2apic mode >>> >>> I guess at that stage we could probably check for x2apic support and >>> scream loudly if it is not present... IMHO. >>> >> Hmm, I think that would the wrong place, > > It has to be the right place because this "Enabled IRQ..." printk above > is from the IRQ remapping code which detects an x2apic mode in your > case. > >> as the initial 3.7.0 configuration didn't have IRQ_REMAP enabled. > > Huh, so why do I see the above message in your dmesg output in > http://marc.info/?l=linux-kernel&m=135540103415652 then? Oh huh, that is the dmesg from 3.4.7, which booted fine. I just sent it hoping it would help to see where the issue comes from. When I run "make oldconfig" for 3.7.0 I accidentally unset CONFIG_IRQ_REMAP, wich also unset CONFIG_X86_X2APIC :( > > Ok, let's sort things out here. Your .config has > > # CONFIG_IRQ_REMAP is not set > > but in the original dmesg you sent, the printk above comes from > intel_irq_remapping.c which gets enabled by CONFIG_IRQ_REMAP. > > So, can you try enabling only CONFIG_IRQ_REMAP and leave > CONFIG_X86_X2APIC off to confirm the original observation? No need, as I said above, the printk comes from a different kernel with a different config. With either CONFIG_IRQ_REMAP=false or CONFIG_X86_X2APIC=false the booting ends in a kernel panic. > > Also, I'd guess your machine can boot with both options off? No, only partly with "noapic", but that makes ahci to fail to detect disks later on. > >> And that was the reason why x2apic got disabled during the "make >> oldconfig" process... >> >> Is this message an indication for missing x2apic? >> >> "smpboot: weird, boot (#255) not listed by the BIOS" > > It's an indication that something is fishy with the apic IDs. > > Thanks. > Cheers, Bernd