Re: 2.6.35-rc1 regression with pvclock and smp guests

Andre Przywara
2010-07-27T11:52:38Z

Avi Kivity wrote:
> On 07/26/2010 11:47 AM, Andre Przywara wrote:
>>> Does this go away with CONFIG_DEBUG_RODATA=n? If so, it's a known
>>> bug in the atomic_*() clobber lists.
>>>
>> Unfortunately the bug persists even with CONFIG_DEBUG_RODATA disabled.
>> The debug options I had enabled now are:
>> CONFIG_DEBUG_DEVRES=y
>> CONFIG_DEBUG_FS=y
>> CONFIG_DEBUG_KERNEL=y
>> CONFIG_DEBUG_BUGVERBOSE=y
>> CONFIG_DEBUG_MEMORY_INIT=y
>> CONFIG_DEBUG_STACKOVERFLOW=y
>> CONFIG_DEBUG_BOOT_PARAMS=y
>>
>> I even disabled all kernel debug options, that does not help, too.
>>
>
> Does changing last_value in arch/x86/kernel/pvclock.c to be non-static help?

No, no change. It still hangs.

> What is the guest executing when it hangs?
Both VCPUs are halted, the monitor and System.map tell me it's in
native_safe_halt().
The code sequence confirms this, it is an intentional sti;hlt condition.
Using -smp 16 also shows that all 16 VCPUs are stuck.

Regards,
Andre.

--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448-3567-12