Comment 0 for bug 1959993

LXC released 4.0.12 as a bugfix release and is now in jammy. We'd like to line things up in focal.
The proposed SRU will bump from 4.0.6 all the way to 4.0.12, lining it up with what's currently in jammy. We've been skipping a few of the bugfix releases in focal so far, mostly catching up when we're starting to see problems with the older version.

In this case, we've seen a number of issues when running with the HWE kernels as well as autopkgtest issues on foreign architectures (arm64 and s390x), all those will go away with this bump as we've confirmed everything is clean in jammy.

Changelog:

  * Cherry-pick upstream bugfixes (stable-4.0):
    - 0002-lxc-checkconfig-Fix-bashism.patch
    - 0003-doc-Fix-reverse-allowlist-denylist.patch

  * New upstream bugfix release (4.0.12):
    (https://discuss.linuxcontainers.org/t/lxc-4-0-12-has-been-released/13288)
    - Fixed CRIU restoration of containers with pre-created veth interfaces
    - Fixed issue with kernels lacking SMT support
    - Extended cgroup2 config options in lxc.mount.auto (cgroup2)
    - lxc-download now relies on HTTPS for validation (avoids GPG issues)

  * New upstream bugfix release (4.0.11):
    (https://discuss.linuxcontainers.org/t/lxc-4-0-11-has-been-released/12427)
    - Core scheduling support (lxc.sched.core)
    - riscv64 support in lxc.arch
    - Significantly improved bash completion profile
    - Greater use of the new VFS mount API (when supported by the kernel)
    - Fix containers with empty network namespaces
    - Handle kernels that lack TIOCGPTPEER
    - Improve CPU bitmask/id handling (handle skipped CPU numbers)
    - Reworked the tests to run offline

  * New upstream bugfix release (4.0.10):
    (https://discuss.linuxcontainers.org/t/lxc-4-0-10-has-been-released/11618)
    - Fix issues with less common architectures
    - Support for additional idmap mounts
    - nft support in lxc-net
    - Cleaner mount entries for sys:mixed
    - Switched GPG server to keyserver.ubuntu.com

  * New upstream bugfix release (4.0.9):
    (https://discuss.linuxcontainers.org/t/lxc-4-0-9-has-been-released/10999)
    - Fix incorrect personality setting when running 32bit containers on 64bit

  * New upstream bugfix release (4.0.8):
    - Fix CGroup attach against older running containers

  * New upstream bugfix release (4.0.7):
    - Testing improvements including fixes from oss-fuzz
    - Rework of the attach codepath
    - Cgroup handling rework

  * Bump to debhelper 12 (allows focal SRUs)
  * Bump standards to 4.6.0.1
  * Add lintian overrides for incorrect bashism detection
  * Remove bash completion install logic (now done upstream)

Just like Ubuntu itself, upstream releases long term support releases, e.g. 4.0, and then periodic point releases including all the accumulated bugfixes.

Only the latest upstream release gets full support from the upstream developers, everyone else is expected to first update to it before receiving any kind of support.

This should qualify under the minor/micro upstream bugfix release allowance of the SRU policy, letting us SRU this without paperwork for every single change included in this upstream release.

[Test case]
lxc has autopkgtests which will assert that the binaries built in -proposed are functional.