Re: [PATCH] kernel/watchdog: fix spurious hard lockups
From: Andi Kleen
Date: Tue Jun 20 2017 - 19:00:29 EST
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.
Reproducer is typically some stress workload that turbos very high.