From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753604AbaIPKAh (ORCPT ); Tue, 16 Sep 2014 06:00:37 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:64013 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753444AbaIPKAe (ORCPT ); Tue, 16 Sep 2014 06:00:34 -0400 Message-ID: <54180A36.7040504@gmail.com> Date: Tue, 16 Sep 2014 18:00:22 +0800 From: Wanpeng Li User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Ingo Molnar , Wanpeng Li CC: Ingo Molnar , hpa@zytor.com, Peter Zijlstra , x86@kernel.org, Borislav Petkov , Yasuaki Ishimatsu , David Rientjes , Prarit Bhargava , Steven Rostedt , Jan Kiszka , Toshi Kani , linux-kernel@vger.kernel.org, Zhang Yang Subject: Re: [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug References: <1406625883-4972-1-git-send-email-wanpeng.li@linux.intel.com> <20140904052034.GA29146@gmail.com> <20140904085641.GA6311@kernel> <20140904093414.GA7296@kernel> <20140916090112.GC4907@gmail.com> In-Reply-To: <20140916090112.GC4907@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 于 14-9-16 下午5:01, Ingo Molnar 写道: > * Wanpeng Li wrote: > >> Hi Ingo, >> On Thu, Sep 04, 2014 at 04:56:41PM +0800, Wanpeng Li wrote: >>> On Thu, Sep 04, 2014 at 07:20:34AM +0200, Ingo Molnar wrote: >>>> * Wanpeng Li wrote: >>>> >>>>> BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 >>>>> IP: [..] find_busiest_group >>>>> PGD 5a9d5067 PUD 13067 PMD 0 >>>>> Oops: 0000 [#3] SMP >>>>> [...] >>>>> Call Trace: >>>>> load_balance >>>>> ? _raw_spin_unlock_irqrestore >>>>> idle_balance >>>>> __schedule >>>>> schedule >>>>> schedule_timeout >>>>> ? lock_timer_base >>>>> schedule_timeout_uninterruptible >>>>> msleep >>>>> lock_device_hotplug_sysfs >>>>> online_store >>>>> dev_attr_store >>>>> sysfs_write_file >>>>> vfs_write >>>>> SyS_write >>>>> system_call_fastpath >>>>> >>>>> Last level cache shared map is built during cpu up and build sched domain >>>>> routine takes advantage of it to setup sched domain cpu topology, however, >>>>> llc shared map is unreleased during cpu disable which lead to invalid sched >>>>> domain cpu topology. This patch fix it by release llc shared map correctly >>>>> during cpu disable. >>>> Very little is said in this changelog about how the bug was >>>> found, how likely it is to occur for others, what systems are >>>> affected, etc. >>> This bug can be triggered by hot add and remove large number of xen >>> domain0's vcpus repeated. >>> >> If I need to send a new version of the patch or you can pick the patch >> w/ the updated changelog for me? ;-) > Please send a fresh new version, maintainers trying to splice & > dice patches and changelogs is an unrobust approach prone to > mistakes. Ok, I will send out a new version tomorrow. ;-) Regards, Wanpeng Li > > Thanks, > > Ingo > -- > 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/