where do I file a bug with xenial 4.4.0-66-generic issue on a kvm hypervisor ?

[Eliezer Croitoru]

Hey List,

I have a DELL r200 server which I am using as a kvm hypervisor with Xenial
for quite some time.
It worked fine but then today I tested an upgrade for the whole server
including the kernel.
The last kernel was:
Linux kvm3 4.4.0-64-generic #85-Ubuntu SMP Mon Feb 20 11:50:30 UTC 2017
x86_64 x86_64 x86_64 GNU/Linux

And worked fine for quite some time.
The latest Xenial kernel from the upgrade (4.4.0-66-generic) causes a very
specific issue.
VM's with virtio nic cannot contact the network.(e1000 works fine)
I have not delved to see if tcpdump sees the packets or something similar in
the hypervisor level and bumped the kernel to 4.6 which I have tested long
ago to work fine.

Where do I file the bug report?
I am pretty sure it's a very series bug but not sure who should be aware of
it and how to debug if it's a machine local one or a wider issue.

Thanks,
Eliezer

----
Eliezer Croitoru
Linux System Administrator
Mobile: +972-5-28704261
Email: eliezer at ngtech.co.il