XEN domU: Guest Rx stalled, unreachable

[Felix Odenkirchen <f.odenkirchen@web.de>]

Dear all,

I'm running a stock Debian SID vm on xen, hostname "vm-sid".
Dom0 is on stock Debian Bullseye, hostname "bigiron-one".

apt updating vm-sid packages on 2022-01-13 08:11:00 UTC rendered vm-sid
unaccessible over network upon reboot.
Updated packages:
bsdutils bsdextrautils dbus eject initramfs-tools libblkid1 libc-bin
libfdisk1 libnss-systemd libpam-systemd libpython3.9-minimal
libpython3.9-stdlib libsmartcols1 libsystemd0 libudev1 libuuid1 mailcap
man-db mount python3-pkg-resources python3.9 python3.9-minimal systemd
systemd-sysv systemd-timesyncd udev util-linux

log messages on dom0:
    12:36:35 felix: /etc/xen/scripts/vif-bridge: online type_if=vif
XENBUS_PATH=backend/vif/18/0
    12:36:35 kernel: [2348158.091840] xenbr0: port 4(vif18.0) entered
blocking state
    12:36:35 kernel: [2348158.091846] xenbr0: port 4(vif18.0) entered
disabled state
    12:36:35 kernel: [2348158.091991] device vif18.0 entered
promiscuous mode
    12:36:35 felix: /etc/xen/scripts/vif-bridge: Successful vif-bridge
online for vif18.0, bridge xenbr0.11:58:39     12:37:14 kernel:
[2348197.078134] vif vif-18-0 vif18.0: Guest Rx ready
    12:37:14 kernel: [2348197.078164] IPv6: ADDRCONF(NETDEV_CHANGE):
vif18.0: link becomes ready
    12:37:14 kernel: [2348197.078235] xenbr0: port 4(vif18.0) entered
blocking state
    12:37:14 kernel: [2348197.078238] xenbr0: port 4(vif18.0) entered
forwarding state
    12:38:49 kernel: [2348292.051684] vif vif-18-0 vif18.0: Guest Rx
stalled
    12:38:49 kernel: [2348292.051759] xenbr0: port 4(vif18.0) entered
disabled state

WORKAROUND:

1. Logging in on virtual console
    felix@bigiron-one:~$ sudo xl console 18

2. bringing interface up manually
    felix@vm-sid:~# sudo ip a
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default qlen 1000
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
           valid_lft forever preferred_lft forever
        inet6 ::1/128 scope host
           valid_lft forever preferred_lft forever
    2: enX0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
        link/ether 00:16:3e:14:07:93 brd ff:ff:ff:ff:ff:ff
    felix@vm-sid:~# sudo ip link set enX0 up
    felix@vm-sid:~# sudo dhclient

3. log on dom0
    12:41:24 kernel: [2348446.972241] vif vif-18-0 vif18.0: Guest Rx ready
    12:41:24 kernel: [2348446.972304] xenbr0: port 4(vif18.0) entered
blocking state
    12:41:24 kernel: [2348446.972308] xenbr0: port 4(vif18.0) entered
forwarding state

4. network running and stable


I fail to see why SID domU stopped bringing up its network interface.
Worked perfectly before.
Another apt update && apt upgrade didn't remove the problem, so no
package fix yet  :-/
All the other domU (Bullseye and Bookworm vm's) are not affected and
running fine,
How can I determine the source of the problem on vm-sid, or the relevant
package?

Regards,
Felix