From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Christoph Lameter <cl@gentwo.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>, Tejun Heo <tj@kernel.org>,
Jet Chen <jet.chen@intel.com>, Su Tao <tao.su@intel.com>,
Yuanhan Liu <yuanhan.liu@intel.com>, LKP <lkp@01.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [scheduler] BUG: unable to handle kernel paging request at 000000000000ce50
Date: Thu, 31 Jul 2014 16:05:17 +0800 [thread overview]
Message-ID: <53D9F8BD.8010205@cn.fujitsu.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1407300954420.4608@gentwo.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 <cl@linux.com>
>
> 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/
>
next prev parent reply other threads:[~2014-07-31 8:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-30 13:56 [scheduler] BUG: unable to handle kernel paging request at 000000000000ce50 Fengguang Wu
2014-07-30 13:58 ` [scheduler] BUG: unable to handle kernel paging request at 000000000000d110 Fengguang Wu
2014-07-30 23:44 ` David Rientjes
2014-07-30 14:55 ` [scheduler] BUG: unable to handle kernel paging request at 000000000000ce50 Christoph Lameter
2014-07-31 8:05 ` Lai Jiangshan [this message]
2014-07-31 10:42 ` Fengguang Wu
2014-08-01 13:54 ` Christoph Lameter
2014-07-31 7:56 ` Lai Jiangshan
2014-08-01 13:58 ` Christoph Lameter
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