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

Paolo Bonzini
2017-02-24T15:17:15Z

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