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

Chris Friesen
2017-02-24T15:10:43Z

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?

Chris