Re: Possible bug? DOM-U network stopped working after fatal error reported in DOM0

["Roger Pau Monné" <roger.pau@citrix.com>]

On Tue, Dec 21, 2021 at 01:13:43AM +0800, G.R. wrote:
> First of all, thank you for your quick response, Juergen and Roger.
> I just realized that I run into mail forwarding issue from sourceforge
> mail alias service, and only found the responses when I checked the
> list archive. As a result, I have to manually merge Roger's response
> to reply...
> 
> > > I have to admit that this trial process is blind as I have no idea
> > > which component in the combo is to be blamed. Is it a bug in the
> > > backend-driver, frontend-driver or the hypervisor itself? Or due to
> > > incompatible versions? Any suggestion on other diagnose ideas (e.g.
> > > debug logs) will be welcome, while I work on the planned experiments.
> >
> > This is a bug in FreeBSD netfront, so no matter which Linux or Xen
> > version you use.
> >
> > Does it make a difference if you disable TSO and LRO from netfront?
> >
> > $ ifconfig xn0 -tso -lro
> It does not, the fatal error still show up after this command.

Thanks for testing.

> >
> > Do you have instructions I can follow in order to try to reproduce the
> > issue?
> I don't know if there are any special details in my setup.
> Hopefully I don't miss anything useful:
> 1. Build a TrueNAS 12.0U7 DOM-U by flushing the OS image into a vdisk
> 2. Create / import a zfs pool to the DOM-U
> 3. Create and share some file based iSCSI extents on the pool
> 4. Mount the iSCSI extent through some initiator clients.
> The domU xn0 should be disabled immediately after step #4.
> 
> I omitted all operational details with the assumption that you are familiar
> with TrueNAS and iSCSI setup.

Not really. Ideally I would like a way to reproduce that can be done
using iperf, nc or similar simple command line tool, without requiring
to setup iSCSI.

> For step #4, I can reproduce it with both ipxe initiator and the win7
> built-in client.
> As a result, I assume the client version does not matter.
> For #2, I actually have a physical disk and controller assigned to DOM-U.
> But I suspect this is probably irrelevant.
> For #3, I'm not sure if the content in the extent matters.
> So far I have been testing the same extent, which is formatted as an NTFS disk.

Can you also paste the output of `ifconfig xn0`?

If I provided a patch for the FreeBSD kernel, would you be able to
apply and test it?

Thanks, Roger.