Re: [PATCH v2] clocksource: Defer override invalidation unless clock is unstable

From: John Stultz
Date: Wed Aug 17 2016 - 16:12:06 EST


On Sat, Aug 6, 2016 at 9:07 AM, Kyle Walker <kwalker@xxxxxxxxxx> wrote:
> Clocksources don't get the VALID_FOR_HRES flag until they have been
> checked by a watchdog. However, when using an override, the
> clocksource_select logic will clear the override value if the
> clocksource is not marked VALID_FOR_HRES during that inititial check.
> When using the boot arguments clocksource=<foo>, this selection can
> run before the watchdog, and can cause the override to be incorrectly
> cleared.
>
> To address this condition, the override_name is only invalidated for
> unstable clocksources. Otherwise, the override is left intact until after
> the watchdog has validated the clocksource as stable/unstable.
>
> Signed-off-by: Kyle Walker <kwalker@xxxxxxxxxx>

Queued for testing and targeting 4.9

thanks
-john