Kernel panic in Hetzner VM after upgrading

[jsnell]

We run OPNsense in Hetzner's virtual servers and if they upgraded beyond 23.1_6 they seem to kernel panic shortly after startup. They work for long enough that the web GUI can be accessed and logged into, but they then panic shortly afterwards. I have attached a screenshot of the panic message from the serial console.

If the machine is restored from the snapshot taken before upgrading, then it continues to work as normal. Also, we have multiple OPNsense VMs, and this seems to affect all of them.

[zan]

In my Hetzner's OPNsense instance I had to blacklist virtio random module from loading otherwise it will cause all sort of funny things like slow boot, high cpu, slow disk/network IO etc

I added this line in /etc/rc.conf.local :

Code Select Expand

devmatch_blacklist="virtio_random.ko"
Worth to try.

Reference: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254513

[jsnell]

Thanks for the suggestion, but this doesn't appear to be the issue in our case. I did investigate further, and this crash seems to be related to a regression in IPv6. If I disable IPv6 on the WAN interface then the server appears stable after the upgrade.