qubes-firewall service fails with "Interrupted system call"

[marmarek]

Observation

openQA test in scenario qubesos-4.3-pull-requests-x86_64-system_tests_network_ipv6@64bit fails in
VmIPv6Networking_debian-13-xfce

Traceback (most recent call last):
  File "/usr/lib64/python3.13/contextlib.py", line 85, in inner
    return func(*args, **kwds)
  File "/usr/lib/python3.13/site-packages/qubes/tests/integ/network.py", line 1434, in test_212_custom_ip_firewall
    self.assertEqual(
    ~~~~~~~~~~~~~~~~^
        self.run_cmd(self.testvm1, self.ping_ip),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        0,
        ^^
        "Ping by IP should be allowed",
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
AssertionError: 1 != 0 : Ping by IP should be allowed

and in journal:

[2026-02-05 14:42:16] [   14.598960] systemd[1]: Started qubes-firewall.service - Qubes firewall updater.
[2026-02-05 14:42:16] [   14.604789] systemd[1]: Starting qubes-network.service - Qubes network forwarding setup...
[2026-02-05 14:42:16]          Starting �[0;1;39mqubes-network.service�[0m - Qubes network forwarding setup...

[2026-02-05 14:42:16] [   14.617766] systemd[1]: Reloading qubes-firewall.service - Qubes firewall updater...
[2026-02-05 14:42:16] [   14.643750] qubes-firewall[780]: Traceback (most recent call last):
[2026-02-05 14:42:16] [   14.660993] qubes-firewall[780]:   File "/usr/bin/qubes-firewall", line 5, in <module>
[2026-02-05 14:42:16] [   14.664294] qubes-firewall[780]:     sys.exit(main())
[2026-02-05 14:42:16] [   14.665207] qubes-firewall[780]:              ~~~~^^
[2026-02-05 14:42:16] [   14.665487] qubes-firewall[780]:   File "/usr/lib/python3/dist-packages/qubesagent/firewall.py", line 684, in main
[2026-02-05 14:42:16] [   14.665648] qubes-firewall[780]:     worker.main()
[2026-02-05 14:42:16] [   14.666910] qubes-firewall[780]:     ~~~~~~~~~~~^^
[2026-02-05 14:42:16] [   14.669159] qubes-firewall[780]:   File "/usr/lib/python3/dist-packages/qubesagent/firewall.py", line 359, in main
[2026-02-05 14:42:16] [   14.669772] qubes-firewall[780]:     self.update_connected_ips(6)
[2026-02-05 14:42:16] [   14.672192] qubes-firewall[780]:     ~~~~~~~~~~~~~~~~~~~~~~~~~^^^
[2026-02-05 14:42:16] [   14.673232] qubes-firewall[780]:   File "/usr/lib/python3/dist-packages/qubesagent/firewall.py", line 461, in update_connected_ips
[2026-02-05 14:42:16] [   14.673511] qubes-firewall[780]:     ips = self.get_connected_ips(family)
[2026-02-05 14:42:16] [   14.674166] qubes-firewall[780]:   File "/usr/lib/python3/dist-packages/qubesagent/firewall.py", line 85, in get_connected_ips
[2026-02-05 14:42:16] [   14.677193] qubes-firewall[780]:     ips = self.qdb.read('/connected-ips6' if family == 6 else '/connected-ips')
[2026-02-05 14:42:16] [   14.677431] qubes-firewall[780]: InterruptedError: [Errno 4] Interrupted system call
[2026-02-05 14:42:16] [   14.694231] systemd[1]: �[0;1;39mqubes-firewall.service: Main process exited, code=exited, status=1/FAILURE�[0m
[2026-02-05 14:42:16] [   14.696164] systemd[1]: �[0;1;38:5:185mqubes-firewall.service: Failed with result 'exit-code'.�[0m
[2026-02-05 14:42:16] [   14.697442] systemd[1]: �[0;1;31mReload failed for qubes-firewall.service - Qubes firewall updater.�[0m
[2026-02-05 14:42:16] [�[0;32m  OK  �[0m] Finished �[0;1;39mqubes-network-uplink@eth0…�[0m Qubes network uplink (eth0) setup.

Test suite description

Reproducible

Fails since (at least) Build 202601221354-4.3

Expected result

Last good: 2026010722-4.3 (or more recent)

Further details

Always latest result in this scenario: latest

[marmarek]

Looks like a fallout of QubesOS/qubes-core-agent-linux#626