Re: XEN domU: Guest Rx stalled, unreachable

[Chuck Zmudzinski <brchuckz@netscape.net>]

On 1/16/2022 7:16 AM, Felix Odenkirchen wrote:
> 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

Hi Felix,

It looks to me like a change in one of the systemd or udev packages in 
vm-sid is causing the trouble here. In my experience with Debian, the 
networking startup stuff is not so straightforward, but I do know that 
systemd and udev are the software components responsible for setting up 
the network and responding to networking events such as plugging in an 
ethernet cable or turning on wifi. So I would look in the changelogs of 
the systemd and udev packages that were updated and see if you can get a 
clue on what might have changed to break your networking startup 
configuration. For example, if your network is setup using 
/etc/network/interfaces and ifup at startup and the systemd 
configuration changed so that the ifup script that reads 
/etc/network/interfaces are no longer called correctly at startup, then 
your network interface would not be brought up automatically at startup. 
In my experience, once when I changed some packages the network 
interface name changed and that caused my network interface to not come 
up properly at startup. To fix it, I had to tweak the systemd configuration.

All the best,

Chuck