Bug#990140: upgrade-reports: lxc-attach does not start with apparmor problem after ugrade to 10.10

[Bernd Breuer <b.breuer@gmx.de>]

Package: upgrade-reports
Severity: normal

Dear Maintainer,

after the recent upgrade to Buster 10.10 (including a kernel upgrade) the command 'lxc-attach' (out of the Linux Container (lxc) set of commands), typed in like

"sudo lxc-attach <container-name>"

stopped working with the error message

"lxc-attach: <container-name>: lsm/lsm.c: lsm_process_label_set_at: 174 Operation not permitted - Failed to set AppArmor label "unconfined"

The conainer itself is starting, but apparmor related config lines like

"lxc.apparmor.profile = unconfined"

produce the above mentioned error, also on another machine after the
same packages upgrade.

I expect lxc-attach to provide me a root shell in the running lxc-container like  it was the case before the recent upgrade.

-- System Information:
Debian Release: 10.10
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-17-amd64 (SMP w/8 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled