Re: [PATCH] kernel/watchdog: fix spurious hard lockups

[Prarit Bhargava]

On 06/20/2017 07:00 PM, Andi Kleen wrote:
> On Tue, Jun 20, 2017 at 06:34:23PM -0400, Prarit Bhargava wrote:
>>
>>
>> On 06/20/2017 05:33 PM, kan.liang@xxxxxxxxx wrote:
>>> From: Kan Liang <Kan.liang@xxxxxxxxx>
>>>
>>> Some users reported spurious NMI watchdog timeouts.
>>>
>>> We now have more and more systems where the Turbo range is wide enough
>>> that the NMI watchdog expires faster than the soft watchdog timer that
>>> updates the interrupt tick the NMI watchdog relies on.
>>>
>>
>> Hmm ... odd that I haven't seen this.  We're running a pretty wide
>> variety of systems here.  Do you have a reproducer?  I'd like to see
>> this occur on production HW.
> 
> It only happens on a few specific CPU SKUs with a very wide Turbo range.

Which ones?

> Reproducer is typically some stress workload that turbos very high.

So stress the single Turbo Max core?  Or any core?

P.

> 
> -Andi
>