lkml.org 
[lkml]   [2019]   [Mar]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] watchdog: Respect watchdog cpumask on CPU hotplug
From
Date


On 3/27/19 8:10 PM, Thomas Gleixner wrote:
> On Wed, 27 Mar 2019, Oleg Nesterov wrote:
>> On 03/26, Thomas Gleixner wrote:
>>>
>>> The rework of the watchdog core to use cpu_stop_work broke the watchdog
>>> cpumask on CPU hotplug.
>>>
>>> The watchdog_enable/disable() functions are now called unconditionally from
>>> the hotplug callback, i.e. even on CPUs which are not in the watchdog
>>> cpumask.
>>>
>>> Only invoke them when the plugged CPU is in the watchdog cpumask.
>>
>> IIUC without this fix an NMI watchdog can too be enabled at boot time even
>> if the initial watchdog_cpumask = housekeeping_cpumask(HK_FLAG_TIMER) doesn't
>> include the plugged CPU.
>
> Yes.
>
>> And after that writing 0 to /proc/sys/kernel/nmi_watchdog clears
>> NMI_WATCHDOG_ENABLED but this can't disable NMI watchdog's outside of
>> watchdog_allowed_mask.
>
> Correct
>
>> So may be this can explain the problem reported by Maxime ?
>> See https://lore.kernel.org/lkml/b99c5a25-a5fe-18dd-2f1d-bdd6834f03e5@redhat.com/
>
> That looks so.

I had a trial with your patch, and I can confirm it fixes my issue:

Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

> Thanks,
>
> tglx
>

\
 
 \ /
  Last update: 2019-03-28 10:38    [W:0.211 / U:0.412 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site