# Re: PROBLEM: virtio\_net LRO kernel panics

- From: Michael S. Tsirkin \<mst@redhat.com\>
- Date: 2021-07-23 12:10:43 
- List: virtualization
- Page: https://ratatoskr.run/virtualization/2021/07/15818124
- Thread: https://ratatoskr.run/virtualization/2021/07/15818124/t.md

```text
On Fri, Jul 23, 2021 at 03:06:04AM -0500, Ivan wrote:
> On Fri, Jul 23, 2021 at 2:59 AM Michael S. Tsirkin [ref] wrote:
> >
> > On Thu, Jul 22, 2021 at 11:50:11PM -0500, Ivan wrote:
> > > On Thu, Jul 22, 2021 at 11:25 PM Jason Wang [ref] wrote:
> > > > 在 2021/7/23 上午10:54, Ivan 写道:
> > > > > On Thu, Jul 22, 2021 at 9:37 PM Jason Wang [ref] wrote:
> > > > >> Does it work if you turn off lro before enabling the forwarding?
> > > > > 0 root@NuRaid:~# ethtool -K eth0 lro off
> > > > > Actual changes:
> > > > > rx-lro: on [requested off]
> > > > > Could not change any device features
> > > >
> > > > Ok, it looks like the device misses the VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
> > > > which makes it impossible to change the LRO setting.
> > > >
> > > > Did you use qemu? If yes, what's the qemu version you've used?
> > >
> > > These are VirtualBox machines, which I've been using for years with
> > > longterm kernels 4.19, and I never had such a problem.  But now that I
> > > tried upgrading to kernels 5.10 or 5.13 -- the panics started.  These
> > > are just generic kernel builds, and a minimalistic userspace.
> >
> > I would be useful to see the features your virtualbox instance provides
> >
> > cat /sys/class/net/eth0/device/features
> 
> # cat /sys/class/net/eth0/device/features
> 1100010110111011111100000000000000000000000000000000000000000000

I was able to reproduce the warning but not the panic.
OTOH if LRO stays on when enabling forwarding that
is already a problem. Any chance you can bisect to
find out which change introduced the panic?

-- 
MST

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