From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754061Ab2LRBMz (ORCPT ); Mon, 17 Dec 2012 20:12:55 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:29653 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753310Ab2LRBMx (ORCPT ); Mon, 17 Dec 2012 20:12:53 -0500 Date: Mon, 17 Dec 2012 20:12:39 -0500 From: Konrad Rzeszutek Wilk To: Sander Eikelenboom Cc: fenghua.yu@intel.com, xen-devel , linux-kernel@vger.kernel.org, hpa@linux.intel.com Subject: Re: 3.8.0-rc0 on xen-unstable: RCU Stall during boot as dom0 kernel after IOAPIC Message-ID: <20121218011239.GB4518@phenom.dumpdata.com> References: <1995613404.20121214165557@eikelenboom.it> <20121216173824.GA4518@phenom.dumpdata.com> <1782021524.20121217213217@eikelenboom.it> <20121217204634.GA13181@konrad-lan.dumpdata.com> <20121217211240.GA13412@konrad-lan.dumpdata.com> <29163327.20121217223558@eikelenboom.it> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <29163327.20121217223558@eikelenboom.it> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 17, 2012 at 10:35:58PM +0100, Sander Eikelenboom wrote: > > Monday, December 17, 2012, 10:12:40 PM, you wrote: > > > On Mon, Dec 17, 2012 at 03:46:34PM -0500, Konrad Rzeszutek Wilk wrote: > >> On Mon, Dec 17, 2012 at 09:32:17PM +0100, Sander Eikelenboom wrote: > >> > > >> > Sunday, December 16, 2012, 6:38:24 PM, you wrote: > >> > > >> > > On Fri, Dec 14, 2012 at 04:55:57PM +0100, Sander Eikelenboom wrote: > >> > >> Hi Konrad, > >> > >> > >> > >> I just tried to boot a 3.8.0-rc0 kernel (last commit: 7313264b899bbf3988841296265a6e0e8a7b6521) as dom0 on my machine with current xen-unstable. > >> > > >> > > Yeah, saw it over the Dec 11->Dec 12 merges and was out on > >> > > vacation during that time (just got back). > >> > > >> > > Did you by any chance try to do a git bisect to narrow down > >> > > which merge it was? > >> > > >> > Hi Konrad, > >> > >> Hey Sander, > >> > >> Thank you for doing the bisection. > >> > >> Fenghua - any ideas what might be amiss in the Xen subsystem? > >> I hadn't looked at the patchset of the CPU0 offlining/onlining > >> so I am not completly up to speed on the particulars of the patches. > > >> > 30106c174311b8cfaaa3186c7f6f9c36c62d17da is the first bad commit > >> > commit 30106c174311b8cfaaa3186c7f6f9c36c62d17da > >> > Author: Fenghua Yu > >> > Date: Tue Nov 13 11:32:41 2012 -0800 > >> > > >> > x86, hotplug: Support functions for CPU0 online/offline > >> > > >> > Add smp_store_boot_cpu_info() to store cpu info for BSP during boot time. > >> > > >> > Now smp_store_cpu_info() stores cpu info for bringing up BSP or AP after > >> > it's offline. > >> > > >> > Continue to online CPU0 in native_cpu_up(). > >> > > >> > Continue to offline CPU0 in native_cpu_disable(). > >> > > >> > Signed-off-by: Fenghua Yu > >> > Link: http://lkml.kernel.org/r/1352835171-3958-5-git-send-email-fenghua.yu@intel.com > >> > Signed-off-by: H. Peter Anvin > >> > > > > This patch: > > > > diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c > > index 353c50f..4f7d259 100644 > > --- a/arch/x86/xen/smp.c > > +++ b/arch/x86/xen/smp.c > > @@ -254,7 +254,7 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus) > > } > > xen_init_lock_cpu(0); > > > > - smp_store_cpu_info(0); > > + smp_store_boot_cpu_info(); > > cpu_data(0).x86_max_cores = 1; > > > > for_each_possible_cpu(i) { > > > Would do the corresponding change in the Xen subsystem that the above > > mentioned commit did. Perhaps that is all that is needed? I am going to > > be able to test this and look in more details tomorrow. > > Seems like it, don't know if there are other things still lurking, but with your patch it boots again as dom0 :-) Excellent. And it seems that it also fixes it on my test machine. Great. I am going to stick Reported-and-Tested-by: Sander Eikelenboom and push it to Linus shortly. Thanks!