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

Herongguang (Stephen)
2017-02-25T01:45:21Z

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.