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

[Huang, Kai]

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 VM2âs 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 VM2âs 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