I'm seeing this as well. Some information that may help. I found the problem with 5.4.0-137. I found that when looking at tcpdump on the guest and the bridge I can see ARP requests on both interfaces. On the guest I can see it responding to the ARP request, however I don't see the ARP response on the bridge interface. I booted back to 5.4.0-126 with Xen and everything is fine.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-meta in Ubuntu. https://bugs.launchpad.net/bugs/2002834 Title: Network bridge issue after updating kernel to 5.4.0-137 Status in linux-meta package in Ubuntu: Confirmed Bug description: Hello, After updating the kernel from 5.4.0-136 to 5.4.0-137 network bridge are not working any more. I can see the bridge with "ip add show" or "brctl show". Network is up and I can reach the full network from the host through the bridge. VM on the host can not reach network or host and host can not reach the VM through the bridge. We have bonded interface used in the bridge and one bridge without IP and one with an IP. DHCP is off on booth bridge. Downgrading the kernel to 5.4.136 (Ubuntu 5.4.0-136.153-generic 5.4.218) seem to work fine. Thank you for your help. Details Description: Ubuntu 20.04.5 LTS Release: 20.04 Not working version => Ubuntu 5.4.0-137.154-generic 5.4.218 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-meta/+bug/2002834/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp