systemd: networkd-test.py fails with newer kinetic kernels

systemd autopkgtests are failing in kinetic, and they are not considered regressions. The failing test is one within networkd-test.py:

======================================================================
ERROR: test_resolved_domain_restricted_dns (__main__.DnsmasqClientTest)
resolved: domain-restricted DNS servers
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/autopkgtest.wTrLDQ/build.Oa5/src/test/networkd-test.py", line 680, in test_resolved_domain_restricted_dns
    out = subprocess.check_output(['resolvectl', 'query', 'math.lab'])
  File "/usr/lib/python3.10/subprocess.py", line 420, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.10/subprocess.py", line 524, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['resolvectl', 'query', 'math.lab']' returned non-zero exit status 1.

----------------------------------------------------------------------
Ran 35 tests in 161.770s

FAILED (errors=1, skipped=2)

The failures started without any changes to the systemd package, i.e. it was caused by another package upload. In particular, the failures started around 2022-11-17 with linux 5.19.0-24.25. The tests pass fine with linux 5.19.0-21.21, i.e. the version in kinetic-release.

This can be demonstrated locally with autopkgtest:

$ autopkgtest --shell-fail systemd --test-name networkd-test.py --pin-packages=kinetic=src:linux --setup-commands 'apt update' -- qemu /home/nr/ubuntu/autopkgtest-testbeds/autopkgtest-kinetic-amd64.img

Note in the above command I did not pass -U, so no packages in the test bed are upgraded. But, with:

$ autopkgtest --shell-fail systemd --test-name networkd-test.py -U -- qemu /home/nr/ubuntu/autopkgtest-testbeds/autopkgtest-kinetic-amd64.img

the kernel is upgraded, and the test fails.

This can also be done manually by grabbing the systemd source on a kinetic machine (e.g. pull-lp-source systemd kinetic), and running:

$ sudo python3 test/networkd-test.py DnsmasqClientTest.test_resolved_domain_restricted_dns

The attached journal.txt shows systemd-resolved logs from when the test is run. The failure is caused by the EHOSTUNREACH when trying to resolve math.lab.
---
ProblemType: Bug
AlsaDevices:
 total 0
 crw-rw---- 1 root audio 116, 1 Mar 9 11:56 seq
 crw-rw---- 1 root audio 116, 33 Mar 9 11:56 timer
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.23.1-0ubuntu3
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CRDA: N/A
CasperMD5CheckResult: unknown
DistroRelease: Ubuntu 22.10
IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig'
Lsusb: Error: command ['lsusb'] failed with exit code 1:
Lsusb-t:

Lsusb-v: Error: command ['lsusb', '-v'] failed with exit code 1:
MachineType: QEMU Standard PC (i440FX + PIIX, 1996)
Package: linux (not installed)
PciMultimedia:

ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 bochs-drmdrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.19.0-35-generic root=UUID=7f0aa1bf-59bd-4d77-b092-7244f86e5566 ro console=tty0 console=hvc0 console=ttyS0
ProcVersionSignature: Ubuntu 5.19.0-35.36-generic 5.19.17
RelatedPackageVersions:
 linux-restricted-modules-5.19.0-35-generic N/A
 linux-backports-modules-5.19.0-35-generic N/A
 linux-firmware 20220923.gitf09bebf3-0ubuntu1.4
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
Tags: kinetic
Uname: Linux 5.19.0-35-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: N/A
_MarkForUpload: True
dmi.bios.date: 04/01/2014
dmi.bios.release: 0.0
dmi.bios.vendor: SeaBIOS
dmi.bios.version: 1.16.0-debian-1.16.0-4
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-i440fx-kinetic
dmi.modalias: dmi:bvnSeaBIOS:bvr1.16.0-debian-1.16.0-4:bd04/01/2014:br0.0:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-kinetic:cvnQEMU:ct1:cvrpc-i440fx-kinetic:sku:
dmi.product.name: Standard PC (i440FX + PIIX, 1996)
dmi.product.version: pc-i440fx-kinetic
dmi.sys.vendor: QEMU