Re: [Qemu-devel] kvm bug in __rmap_clear_dirty during live migration

fangying
2017-03-13T14:59:41Z

Hi, Huang Kai

After weeks of intensive testing, we think the problem is solved and
this issue can be closed.

On 2017/2/27 15:38, Huang, Kai wrote:
>
>
> On 2/25/2017 2:44 PM, Herongguang (Stephen) wrote:
>>
>>
>> On 2017/2/24 23:14, Paolo Bonzini wrote:
>>>
>>>
>>> On 24/02/2017 16:10, Chris Friesen wrote:
>>>> On 02/23/2017 08:23 PM, Herongguang (Stephen) wrote:
>>>>
>>>>> On 2017/2/22 22:43, Paolo Bonzini wrote:
>>>>
>>>>>> Hopefully Gaohuai and Rongguang can help with this too.
>>>>>>
>>>>>> Paolo
>>>>>
>>>>> Yes, we are looking into and testing this.
>>>>>
>>>>> I think this can result in any memory corruption, if VM1 writes its
>>>>> PML buffer into VM2’s VMCS (since sched_in/sched_out notifier of VM1
>>>>> is not registered yet), then VM1 is destroyed (hence its PML buffer
>>>>> is freed back to kernel), after that, VM2 starts migration, so CPU
>>>>> logs VM2’s dirty GFNS into a freed memory, results in any memory
>>>>> corruption.
>>>>>
>>>>> As its severity, this commit
>>>>> (http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4e59516a12a6ef6dcb660cb3a3f70c64bd60cfec)
>>>>>
>>>>>
>>>>>
>>>>> is eligible to back port to kernel stable.
>>>>
>>>> Are we expecting that fix to resolve the original issue, or is it a
>>>> separate issue that needs fixing in stable?
>>>
>>> It should be the original issue.
>>>
>>> Paolo
>>>
>>> .
>>>
>> Yes, I agree, though we are still testing.
>>
>>
> Hi Stephen,
>
> Sorry for late reply. I was taking the whole week off last week. How's
> the test going?
>
> Thanks,
> -Kai
>
> .
>