Re: rcu_preempt self-detected stall on CPU from 4.5-rc3, since 3.17

[John Stultz]

On Thu, Feb 18, 2016 at 7:56 PM, Ross Green <rgkernel@xxxxxxxxx> wrote:
> Well a bonus extra!
> Kept everything running and there was another stall.
> So i have included the demsg output for perusal.
>
> Just to clear things up there is no hotplug involved in this system.
> It is a standard Pandaboard ES Ti4460 two processor system.
> I use this for testing as a generic armv7 processor, plus can keep it
> just running along for testing for a long time. the system has a total
> of 23-25 process running on average. Mainly standard daemons. There is
> certainly no heavy processing going on. I run a series of benchmarks
> that are cpu intensive for the first 20 miinutes after boot and then
> just leave it idle away. checking every so often to see how it has
> gone.
> As mentioned I have observed these stalls going back to 3.17 kernel.
> It will often take up to a week to record such a stall. I will
> typically test every new release kernel, so the -rc? series will get
> around a weeks testing.

Sorry. Kind of hopping in a bit late here. Is this always happening
with just the pandaboard? Or are you seeing this on different
machines?

Have you tried enabling CONFIG_DEBUG_TIMEKEEPING just in case
something is going awry there?

thanks
-john