Re: KVM on POWER8 host lock up since 10d91611f426 ("powerpc/64s: Reimplement book3s idle code in C")

[Ruediger Oertel <ro@suse.de>]

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Am 31.08.20 um 03:14 schrieb Nicholas Piggin:

> So hwthread_state is never getting back to to HWTHREAD_IN_IDLE on
> those threads. I wonder what they are doing. POWER8 doesn't have a good
> NMI IPI and I don't know if it supports pdbg dumping registers from the
> BMC unfortunately.


> Do the messages always come in pairs of CPUs?

well,
- one problem is that at some point the machine just locks up completely,
  so I can not tell if there were lines not printed any more and in some
  cases all I get is a single line
- looking at the stats in generally it's either one cpu printed several
  times or a pair ("not strictly") alternatingly

2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.029821] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.058630] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.108268] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.210206] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.323465] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.334420] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.345470] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.395185] KVM: couldn't grab cpu 92
2020-07-30T03:16:16+00:00 obs-power8-03 kernel: [51284.517182] KVM: couldn't grab cpu 92
2020-07-30T03:16:17+00:00 obs-power8-03 kernel: [51284.600716] KVM: couldn't grab cpu 92
2020-07-30T03:16:18+00:00 obs-power8-03 kernel: [51286.201589] KVM: couldn't grab cpu 92
2020-07-30T03:16:19+00:00 obs-power8-03 kernel: [51286.627273] KVM: couldn't grab cpu 92

2020-07-30T16:44:16+00:00 obs-power8-04 kernel: [30099.726288] KVM: couldn't grab cpu 61
2020-07-30T16:44:16+00:00 obs-power8-04 kernel: [30099.736843] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.747429] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.877138] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.916422] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30099.931755] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.029003] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.334895] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.392713] KVM: couldn't grab cpu 61
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.569011] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.617048] KVM: couldn't grab cpu 125
2020-07-30T16:44:17+00:00 obs-power8-04 kernel: [30100.628107] KVM: couldn't grab cpu 125
2020-07-30T16:44:18+00:00 obs-power8-04 kernel: [30100.809046] KVM: couldn't grab cpu 125
2020-07-30T16:44:18+00:00 obs-power8-04 kernel: [30101.001097] KVM: couldn't grab cpu 61
2020-07-30T16:44:19+00:00 obs-power8-04 kernel: [30102.109007] KVM: couldn't grab cpu 125
2020-07-30T16:44:19+00:00 obs-power8-04 kernel: [30102.254470] KVM: couldn't grab cpu 61



> 
> I'm not sure where to start with reproducing, I'll have to try. How many
> vCPUs in the guests? Do you have several guests running at once?
> 
> Thanks,
> Nick
> 


-- 
with kind regards (mit freundlichem Grinsen),
  Ruediger Oertel (ro@suse.com,ro@suse.de,bugfinder@t-online.de)
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