Re: [Xen-devel] High CPU temp, suspend problem - xen 4.1.5-pre, linux 3.7.x

[Marek Marczykowski <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On 27.03.2013 15:46, Andrew Cooper wrote:
> On 27/03/2013 14:31, Marek Marczykowski wrote:
>> On 27.03.2013 09:52, Jan Beulich wrote:
>>>>>> On 26.03.13 at 19:50, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>>>> So vector e9 doesn't appear to be programmed in anywhere.
>>> Quite obviously, as it's the 8259A vector for IRQ 9. The question
>>> really is why an IRQ appears on that vector in the first place. The
>>> 8259A resume code _should_ leave all IRQs masked on a fully
>>> IO-APIC system (see my question raised yesterday).
>>>
>>> And that's also why I suggested, for an experiment, to fiddle with
>>> the loop exit condition to exclude legacy vectors (which wouldn't
>>> be a final solution, but would at least tell us whether the direction
>>> is the right one). In the end, besides understanding why an
>>> interrupt on vector E9 gets raised at all, we may also need to
>>> tweak the IRQ migration logic to not do anything on legacy IRQs,
>>> but that would need to happen earlier than in
>>> smp_irq_move_cleanup_interrupt(). Considering that 4.3
>>> apparently doesn't have this problem, we may need to go hunt for
>>> a change that isn't directly connected to this, yet deals with the
>>> problem as a side effect (at least I don't recall any particular fix
>>> since 4.2). One aspect here is the double mapping of legacy IRQs
>>> (once to their IO-APIC vector, and once to their legacy vector,
>>> i.e. vector_irq[] having two entries pointing to the same IRQ).
>> So tried change loop condition to LAST_DYNAMIC_VECTOR and it doesn't hit that
>> BUG/ASSERT. But still it doesn't work - only CPU0 used by scheduler, also 
>> some
>> errors from dom0 kernel, and errors about PCI devices used by domU(1).
>>
>> Messages from resume (different tries):
>> http://duch.mimuw.edu.pl/~marmarek/qubes/xen-4.1-last-dynamic-vector.log
>> http://duch.mimuw.edu.pl/~marmarek/qubes/xen-4.1-last-dynamic-vector2.log
>>
>> Also one time I've got fatal page fault error, earlier in resume (it isn't
>> deterministic):
>> http://duch.mimuw.edu.pl/~marmarek/qubes/xen-4.1-resume-page-fault.log
>>
> 
> This pagefault is a Null structure pointer dereference, likely the
> scheduling data.  At a first glance, it looks related to the assertion
> failures I have been seeing sporadically in testing, but unable to
> reproduce reliably.  There seems to be something quite dodgy with
> interaction of vcpu_wake and scheduling loops.
> 
> The other logs indicate that dom0 appears to have a domain id of 1,
> which is sure to cause problems.

Perhaps not - domain 1 exists and have some PCI devices assigned (namely two
network adapters).

> As for locating the cause of the legacy vectors, it might be a good idea
> to stick a printk at the top of do_IRQ() which indicates an interrupt
> with vector between 0xe0 and 0xef.  This might at least indicate whether
> legacy vectors are genuinely being delivered, or whether we have some
> memory corruption causing these effects.

Ok, will try something like this.

-- 
Best Regards / Pozdrawiam,
Marek Marczykowski
Invisible Things Lab

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