Comment 2 for bug 1683947

Hey Jay,

I found this same issue here -- https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1685416 -- when debugging WireGuard issues on GCE. I'm curious how you found it and what your debugging was like. Do you work for Google and could debug their virtio implementation? I spent a really long time just rebuilding things and tweaking stuff and following the skb all the way down to the output path. When I had nearly given up, I thought, "you know, maybe I really _should_ take a look at this virtio header stuff." After setting that flag back to zero, and seeing what other successful packets were doing, I had figured it out. At first I thought it was a real kernel bug, and then later saw it was a backporting issue and hence reported it. Anyway, really traumatic debugging blitz that extended through the night. I'm curious about your story...

Jason