Bug#1035779: linux-image-5.10.0-22: kvm/qemu kernel null pointer dereference, VM doesn't start

[Jared Epp <jaredepp@pm.me>]

Hi Salvatore,

Thanks for the quick reply!

> > 
> > This sounds similar to the
> > https://forum.proxmox.com/threads/with-latest-5-15-104-1-pve-windows-server-vm-freeze-stuck.125294/
> > issue. Would you be able to verify two things:
> > 
> > Check how the Windows VM is configured and if you pass the
> > '+hv-tlbflush' flag.
> > 

You're right, I am passing this flag. In libvirt I use:

<domain>
  <features>
    <hyperv>
      <tlbflush state='on'/>
    </hyperv>
  </features>
</domain>

I tried this fix first and it works. If I reboot into 5.10.0-22-amd64, and instead set <tlbflush state='off'/> above, the VM boots.

> > Additionally, would the attached patch make the issue go away?

Thanks for the patch; it does fix the issue.  I set this back: <tlbflush state='on'/>, applied your patch to 5.10.0-22-amd64 and booted my newly patched kernel, and the VM boots.

> 
> 
> Now with patch attached.
> 
> Regards,
> Salvatore

Thanks for your help.  This is my first time using the BTS so I hope I've done everything correctly. If there's anything else I should do, or if you want me to test something, let me know.

Jared