[1021042] upgrades: When testing dist upgrade, unattended-upgrade stuck in loop consuming 100% cpu

FreedomBox v22.20 in vagrant bullseye box, after running all functional tests, then testing dist upgrade to bookworm.

freedombox-dist-upgrade log:

-- Journal begins at Fri 2022-05-13 15:56:59 EET. --
Sep 16 13:59:29 freedombox systemd[1]: Starting Upgrade to new stable Debian release...
Sep 16 13:59:30 freedombox upgrades[333804]: Taking a snapshot before dist upgrade...
Sep 16 13:59:30 freedombox upgrades[333804]: Apt snapshots already disabled.
Sep 16 13:59:30 freedombox upgrades[333804]: Disabling searx...
Sep 16 13:59:31 freedombox upgrades[333804]: Holding freedombox package...
Sep 16 13:59:31 freedombox upgrades[333893]: freedombox set on hold.
Sep 16 13:59:31 freedombox upgrades[333804]: Updating Apt cache...
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:31 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:1:0.0000:Retrieving file 1 of 4
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:6:0.0000:Retrieving file 6 of 8
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:6:0.0000:Retrieving file 6 of 8
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:6:0.0000:Retrieving file 6 of 8
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:8:0.0000:Retrieving file 8 of 12
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:8:0.0000:Retrieving file 8 of 12
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:8:0.0000:Retrieving file 8 of 12
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:8:0.0000:Retrieving file 8 of 12
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:13:0.0000:Retrieving file 13 of 16
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:13:0.0000:Retrieving file 13 of 16
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:13:0.0000:Retrieving file 13 of 16
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:13:0.0000:Retrieving file 13 of 16
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:21:18.2502:Retrieving file 21 of 23
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:21:18.2502:Retrieving file 21 of 23
Sep 16 13:59:32 freedombox upgrades[333898]: dlstatus:21:33.1859:Retrieving file 21 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:21:49.1900:Retrieving file 21 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:21:51.3546:Retrieving file 21 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:21:51.3686:Retrieving file 21 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:21:77.8637:Retrieving file 21 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:21:77.8841:Retrieving file 21 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:21:97.3913:Retrieving file 21 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:22:98.2609:Retrieving file 22 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:22:98.2609:Retrieving file 22 of 23
Sep 16 13:59:33 freedombox upgrades[333898]: dlstatus:22:98.2609:Retrieving file 22 of 23
Sep 16 13:59:34 freedombox upgrades[333898]: dlstatus:23:99.1304:Retrieving file 23 of 23
Sep 16 13:59:34 freedombox upgrades[333898]: dlstatus:23:99.1304:Retrieving file 23 of 23
Sep 16 13:59:34 freedombox upgrades[333898]: dlstatus:23:99.1304:Retrieving file 23 of 23
Sep 16 13:59:34 freedombox upgrades[333898]: dlstatus:23:100.0000:Retrieving file 23 of 23
Sep 16 13:59:35 freedombox upgrades[333804]: Upgrading packages: ['base-files']...
Sep 16 13:59:35 freedombox upgrades[334240]: dlstatus:1:0.0000:Retrieving file 1 of 1
Sep 16 13:59:35 freedombox upgrades[334240]: dlstatus:1:0.0000:Retrieving file 1 of 1
Sep 16 13:59:35 freedombox upgrades[334240]: dlstatus:1:0.0000:Retrieving file 1 of 1
Sep 16 13:59:35 freedombox upgrades[334240]: dlstatus:1:0.0000:Retrieving file 1 of 1
Sep 16 13:59:35 freedombox upgrades[334240]: dlstatus:1:0.0000:Retrieving file 1 of 1
Sep 16 13:59:35 freedombox upgrades[334240]: dlstatus:1:1.5738:Retrieving file 1 of 1
Sep 16 13:59:35 freedombox upgrades[334240]: dlstatus:1:100.0000:Retrieving file 1 of 1
Sep 16 13:59:35 freedombox upgrades[334240]: pmstatus:dpkg-exec:0.0000:Running dpkg
Sep 16 13:59:35 freedombox upgrades[334240]: pmstatus:base-files:0.0000:Preparing base-files (amd64)
Sep 16 13:59:36 freedombox upgrades[334240]: pmstatus:base-files:20.0000:Unpacking base-files (amd64)
Sep 16 13:59:36 freedombox upgrades[334240]: pmstatus:base-files:40.0000:Installing base-files (amd64)
Sep 16 13:59:36 freedombox upgrades[334240]: pmstatus:dpkg-exec:40.0000:Running dpkg
Sep 16 13:59:36 freedombox upgrades[334240]: pmstatus:base-files:40.0000:Preparing to configure base-files (amd64)
Sep 16 13:59:36 freedombox upgrades[334240]: pmstatus:base-files:60.0000:Configuring base-files (amd64)
Sep 16 13:59:36 freedombox upgrades[334240]: pmstatus:base-files:80.0000:Installed base-files (amd64)
Sep 16 13:59:36 freedombox upgrades[334240]: pmstatus:dpkg-exec:80.0000:Running dpkg
Sep 16 13:59:36 freedombox upgrades[333804]: Setting debconf selections: ['grub-pc grub-pc/install_devices_empty boolean true']
Sep 16 13:59:37 freedombox upgrades[333804]: Running unattended-upgrade...
Sep 16 13:59:37 freedombox upgrades[334341]: Starting unattended upgrades script
Sep 16 13:59:37 freedombox upgrades[334341]: Allowed origins are: origin=Debian,codename=bookworm,label=Debian, origin=Debian,codename=bookworm,label=Debian-Security, origin=Debian,codename=bookworm-security,label=Debian-Security, o=Debian Backports,a=bookworm-backports,l=Debian Backports
Sep 16 13:59:37 freedombox upgrades[334341]: Initial blacklist:
Sep 16 13:59:37 freedombox upgrades[334341]: Initial whitelist (not strict):
Sep 16 14:07:21 freedombox upgrades[334341]: package libinput-bin upgradable but fails to be marked for upgrade (E:Unable to correct problems, you have held broken packages.)

The process was stuck at this point for over 30 minutes.

Possibly related to https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1012752.