From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932236AbaGaID7 (ORCPT ); Thu, 31 Jul 2014 04:03:59 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:61996 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S932185AbaGaIDz (ORCPT ); Thu, 31 Jul 2014 04:03:55 -0400 X-IronPort-AV: E=Sophos;i="5.00,1001,1396972800"; d="scan'208";a="34007139" Message-ID: <53D9F8BD.8010205@cn.fujitsu.com> Date: Thu, 31 Jul 2014 16:05:17 +0800 From: Lai Jiangshan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: Christoph Lameter CC: Fengguang Wu , Tejun Heo , Jet Chen , Su Tao , Yuanhan Liu , LKP , Subject: Re: [scheduler] BUG: unable to handle kernel paging request at 000000000000ce50 References: <20140730135616.GK16537@localhost> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.103] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/30/2014 10:55 PM, Christoph Lameter wrote: > On Wed, 30 Jul 2014, Fengguang Wu wrote: > >> FYI, this commit seems to convert some kernel boot hang bug into >> different BUG messages. > > Hmmm. Still a bit confused as to why these messages occur.. Does this > patch do any good? The vmstat bug can't propagate to scheduler. I also hope the following patch to be tested earlier for the vmstat bug. > > > Subject: vmstat ondemand: Fix online/offline races > > Do not allow onlining/offlining while the shepherd task is checking > for vmstat threads. > > On offlining a processor do the right thing cancelling the vmstat > worker thread if it exista and also exclude it from the shepherd > process checks. > > Signed-off-by: Christoph Lameter > > Index: linux/mm/vmstat.c > =================================================================== > --- linux.orig/mm/vmstat.c 2014-07-30 09:35:54.602662306 -0500 > +++ linux/mm/vmstat.c 2014-07-30 09:43:07.109037043 -0500 > @@ -1317,6 +1317,7 @@ static void vmstat_shepherd(struct work_ > { > int cpu; > > + get_online_cpus(); > /* Check processors whose vmstat worker threads have been disabled */ > for_each_cpu(cpu, cpu_stat_off) > if (need_update(cpu) && > @@ -1325,6 +1326,7 @@ static void vmstat_shepherd(struct work_ > schedule_delayed_work_on(cpu, &per_cpu(vmstat_work, cpu), > __round_jiffies_relative(sysctl_stat_interval, cpu)); > > + put_online_cpus(); > > schedule_delayed_work(&shepherd, > round_jiffies_relative(sysctl_stat_interval)); > @@ -1380,8 +1382,8 @@ static int vmstat_cpuup_callback(struct > break; > case CPU_DOWN_PREPARE: > case CPU_DOWN_PREPARE_FROZEN: > - if (!cpumask_test_and_set_cpu(cpu, cpu_stat_off)) > - cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu)); > + cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu)); > + cpumask_clear_cpu(cpu, cpu_stat_off); > break; > case CPU_DOWN_FAILED: > case CPU_DOWN_FAILED_FROZEN: > -- > 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/ >