Re: [Xen-devel] cpuidle and un-eoid interrupts at the local apic

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 05/08/13 13:45, Jan Beulich wrote:
>>>> On 03.08.13 at 01:32, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>> Adjusted from my "interesting" idea of printk formatting,
>>
>> (XEN) **Pending EOI error
>> (XEN)   irq 29, vector 0x2e
>> (XEN)   s[0] irq 29, vec 0x2e, ready 0, ISR 1, TMR 0, IRR 0
>> (XEN) All LAPIC state:
>> (XEN) [vector]      ISR      TMR      IRR
>> (XEN) [1f:01] 00000000 00000000 00000000
>> (XEN) [3f:20] 00016384 4095716568 00000000
>> (XEN) [5f:40] 00000000 4041382474 00000000
>> (XEN) [7f:60] 00000000 3967325758 00000000
>> (XEN) [9f:80] 00000000 2123395250 00000000
>> (XEN) [bf:a0] 00000000 1502837374 00000000
>> (XEN) [df:c0] 00000000 4270415335 00000000
>> (XEN) [ff:e0] 00000000 00000000 00000000
>>
>> So Xen has been interrupted by an interrupt which it believes it has
>> already seen, and is outstanding on the PendingEOI stack, waiting for
>> Dom0 to actually deal with.
> And which hence should be masked. Is this perhaps a non-maskable
> MSI, and the device (erroneously?) issues a new interrupts before
> the old one was really finished with?
>
> Jan
>

All of these crashes are coming out of mwait_idle, so the cpu in
question has literally just been in an lower power state.

I am wondering whether there is some caching issue where an update to
the Pending EOI stack pointer got "lost", but this seems like a little
too specific to be reasonably explained as a caching issue.

A new debugging patch is on its way (Sorry - it has been a very busy few
days)

~Andrew

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