On another tangent, I wonder if the change that brought this to light was the switch to booting without initrd. The timing is about right, and fits with the fact that it doesn't occur with the generic kernel (which cannot boot without initrd in Azure). So if someone has an excess of time to test <wink>, testing bionic but with initrdless boot and focal with initrdful boot would be interesting. I don't know exactly what runes have to be cast to do this.
Getting the udevd debug output is still higher priority though.
On another tangent, I wonder if the change that brought this to light was the switch to booting without initrd. The timing is about right, and fits with the fact that it doesn't occur with the generic kernel (which cannot boot without initrd in Azure). So if someone has an excess of time to test <wink>, testing bionic but with initrdless boot and focal with initrdful boot would be interesting. I don't know exactly what runes have to be cast to do this.
Getting the udevd debug output is still higher priority though.