apparmor error while removing python3.7 in lxd

[Andreas Hasenack]

In a focal LXD container, I was replacing python3.7 with python3.8. At the end, I ran autoremove to get rid of the last python3.7 pieces, and this happened:

$ sudo apt autoremove
sudo: setrlimit(RLIMIT_CORE): Operation not permitted
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  libfreetype6 libpython3.7 libpython3.7-dev libpython3.7-minimal libpython3.7-stdlib python3.7-minimal
0 upgraded, 0 newly installed, 6 to remove and 55 not upgraded.
After this operation, 46.9 MB disk space will be freed.
Do you want to continue? [Y/n]
(Reading database ... 60389 files and directories currently installed.)
Removing libfreetype6:amd64 (2.10.1-2) ...
Removing libpython3.7-dev:amd64 (3.7.6-1ubuntu2) ...
Removing libpython3.7:amd64 (3.7.6-1ubuntu2) ...
Removing libpython3.7-stdlib:amd64 (3.7.6-1ubuntu2) ...
Removing python3.7-minimal (3.7.6-1ubuntu2) ...
Unlinking and removing bytecode for runtime python3.7
update-binfmts: warning: unable to open /proc/sys/fs/binfmt_misc/python3.7 for writing: Permission denied
update-binfmts: warning: unable to disable binary format python3.7
update-binfmts: exiting due to previous errors
dpkg: error processing package python3.7-minimal (--remove):
 installed python3.7-minimal package pre-removal script subprocess returned error exit status 2
dpkg: too many errors, stopping
Errors were encountered while processing:
 python3.7-minimal
Processing was halted because there were too many errors.
sudo apt-get bE: Sub-process /usr/bin/dpkg returned an error code (1)

dmesg shows the apparmor DENIED messages:
[1960915.476179] audit: type=1400 audit(1581063070.923:4252): apparmor="DENIED" operation="mount" info="failed flags match" error=-13 profile="lxd-andreas-focal-isc-kea_</var/snap/lxd/common/lxd>" name="/run/systemd/unit-root/snap/" pid=513284 comm="(fwupdmgr)" flags="ro, remount, noatime, bind"
[1960915.514190] audit: type=1400 audit(1581063070.963:4253): apparmor="DENIED" operation="mount" info="failed flags match" error=-13 profile="lxd-andreas-focal-isc-kea_</var/snap/lxd/common/lxd>" name="/run/systemd/unit-root/boot/" pid=513294 comm="(fwupd)" flags="ro, remount, noatime, bind"
[1964558.405803] audit: type=1400 audit(1581066713.861:4254): apparmor="DENIED" operation="mount" info="failed flags match" error=-13 profile="lxd-paride-ff_</var/snap/lxd/common/lxd>" name="/run/systemd/unit-root/snap/" pid=525393 comm="(fwupdmgr)" flags="ro, remount, noatime, bind"
[1964558.440736] audit: type=1400 audit(1581066713.897:4255): apparmor="DENIED" operation="mount" info="failed flags match" error=-13 profile="lxd-paride-ff_</var/snap/lxd/common/lxd>" name="/run/systemd/unit-root/boot/" pid=525404 comm="(fwupd)" flags="ro, remount, noatime, bind"

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: binfmt-support 2.2.0-2
ProcVersionSignature: Ubuntu 5.4.0-9.12-generic 5.4.3
Uname: Linux 5.4.0-9-generic x86_64
ApportVersion: 2.20.11-0ubuntu16
Architecture: amd64
Date: Fri Feb 7 13:02:00 2020
ProcEnviron:
 TERM=screen-256color
 PATH=(custom, no user)
 LANG=C.UTF-8
 SHELL=/bin/bash
SourcePackage: binfmt-support
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.