[Crash-utility] question about phys_base

[Wen Congyang]

At 02/17/2012 10:20 PM, Dave Anderson Wrote:
> 
> 
> ----- Original Message -----
>> At 02/17/2012 12:30 AM, Dave Anderson Wrote:
> 
>>>> Yes. Even if the guest is linux, it is still impossible to do it.  Because
>>>> the guest maybe in the second kernel.
>>>>
>>>> qemu-dump walks all guest's page table and collect virtual address and
>>>> physical address mapping. If the page is not used by guest, the virtual is set
>>>> to 0.  I create PT_LOAD according to such mapping. So if the guest linux,
>>>> there may be a PT_LOAD segment that describes __START_KERNEL_map region.
>>>> But the information stored in PT_LOAD maybe for the second kernel. If crash
>>>> uses it, crash will see the second kernel, not the first kernel.
>>>
>>> Just to be clear -- what do you mean by the "second" kernel?  Do you
>>> mean that a guest kernel crashed guest, and did a kdump operation,
>>> and that second kdump kernel failed somehow, and now you're trying
>>> to do a "virsh dump" on the kdump kernel?
>>
>> Yes, the second kernel means kdump kernel. If kdump failed, the user can
>> use it to dump the guest's memory.
> 
> OK, so will your code present two different "types" of ELF headers?

I donot understand what do you want to say.
Do you mean there is two ELF headers in qemu-generated vmcore?

Thanks
Wen Congyang

> 
> Dave
>