From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753163AbaIOBcg (ORCPT ); Sun, 14 Sep 2014 21:32:36 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:60462 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753084AbaIOBce (ORCPT ); Sun, 14 Sep 2014 21:32:34 -0400 Message-ID: <541641A9.1060300@gmail.com> Date: Mon, 15 Sep 2014 09:32:25 +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: 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> In-Reply-To: <20140904093414.GA7296@kernel> 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 Ping Ingo, HPA, PeterZ 于 14-9-4 下午5:34, Wanpeng Li 写道: > 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? ;-) > > Regards, > Wanpeng Li > >> 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/