Re: [PATCH 5.12 123/363] watchdog: cleanup handling of false positives

From: Petr Mladek
Date: Mon May 17 2021 - 10:35:44 EST

On Mon 2021-05-17 15:59:49, Greg Kroah-Hartman wrote:
> From: Petr Mladek <pmladek@xxxxxxxx>
> [ Upstream commit 9bf3bc949f8aeefeacea4b1198db833b722a8e27 ]
> Commit d6ad3e286d2c ("softlockup: Add sched_clock_tick() to avoid kernel
> warning on kgdb resume") introduced touch_softlockup_watchdog_sync().


> Make the code more straightforward:
> 1. Always call kvm_check_and_clear_guest_paused() at the very
> beginning to handle PVCLOCK_GUEST_STOPPED. It touches the watchdog
> when the quest did sleep.
> 2. Handle the situation when the watchdog has been touched
> Call sched_clock_tick() when touch_*sync() variant was used. It makes
> sure that the timestamp will be up to date even when it has been
> touched in atomic context or quest did sleep.
> As a result, kvm_check_and_clear_guest_paused() is called on a single
> location. And the right timestamp is always set when returning from the
> timer callback.
> Link:

Please, remove this patch from the stable backport. It might
cause false softlockup reports, see

Best Regards,