[linuxkernel] Add Super Long Term Support (SLTS)

[BiNZGi]

Browsing on https://en.wikipedia.org/wiki/Linux_kernel_version_history I saw that there are release cycles that get Super Long Term Support (SLTS):

After that, versions designated as Super-Long-Term Support (SLTS) will then be maintained by the Civil Infrastructure Platform (CIP) for many more years.

We should list these versions with an additional extendedSupport entry and explain the SLTS in the description.

[captn3m0]

That page isn't very clear, so summarizing whatever details I could find.

1. There are four SLTS branches: 4.4, and 4.19, 5.10, 6.1.
2. 4.19 is in both LTS and SLTS since it is supported till 2024-12-31 via LTS, but CIP seems to have already released a 4.19-cip branch. Similar goes for 5.10, and 6.1
3. 4.4 entered SLTS on Feb 2022, after the LTS support ended with the release of 4.4.302.
4. There's -rt (realtime) branches published for all supported kernels as well.
5. Similar to the upstream linux, cip releases are source-only, no binaries

https://wiki.linuxfoundation.org/civilinfrastructureplatform/start has better guidance, and I found this older table via this blog:

Another good source is https://gitlab.com/cip-project/cip-lifecycle, which I managed to run manually to generate the following information:

CIP Kernel Lifecycle Summary

LTS kernel
  LTS kernel 4.4
    2016-01-10 - 2022-02-01
  LTS kernel 4.19
    2018-10-22 - 2024-12-01
  LTS kernel 5.10
    2020-12-13 - 2026-12-01
CIP kernel
  CIP kernel 4.4
    phase1: 2017-01-17 - 2022-02-01
    phase2: 2022-02-01 - 2027-01-01
  CIP kernel 4.4-rt
    phase1: 2017-11-16 - 2022-02-01
    phase2: 2022-02-01 - 2027-01-01
  CIP kernel 4.19(-rt)
    phase1: 2019-01-11 - 2024-12-01
    phase2: 2024-12-01 - 2029-01-01
  CIP kernel 5.10
    phase1: 2021-12-05 - 2026-12-01
    phase2: 2026-12-01 - 2031-01-01
  CIP kernel 5.10-rt
    phase1: 2021-12-08 - 2026-12-01
    phase2: 2026-12-01 - 2031-01-01
Debian
  Debian 8
    testing: 2013-05-04 - 2015-04-25
    stable: 2015-04-25 - 2018-06-17
    LTS: 2018-06-17 - 2020-06-30
    ELTS: 2020-07-01 - 2022-06-30
  Debian 10
    testing: 2017-06-17 - 2019-07-06
    stable: 2019-07-06 - 2022-08-01
    LTS: 2022-08-01 - 2024-08-01 (Predicted)
    ELTS: 2024-08-01 - 2026-08-01 (Predicted)
  Debian 11
    testing: 2019-07-06 - 2021-08-14 (Predicted)
    stable: 2021-08-14 - 2024-08-14 (Predicted)
    LTS: 2024-08-14 - 2026-08-14 (Predicted)
    ELTS: 2026-08-14 - 2028-08-14 (Predicted)
  Debian 12
    testing: 2021-08-14 - 2023-08-14 (Predicted)
    stable: 2023-08-14 - 2026-08-14 (Predicted)
    LTS: 2026-08-14 - 2028-08-14 (Predicted)
    ELTS: 2028-08-14 - 2030-08-14 (Predicted)
CIP Core
  CIP Core (Debian 8)
    phase1: 2015-04-25 - 2022-06-30
    phase2: 2022-06-30 - 2027-01-01
  CIP Core (Debian 10)
    phase1: 2019-07-06 - 2026-08-01 (Predicted)
    phase2: 2026-08-01 - 2029-01-01
  CIP Core (Debian 11)
    phase1: 2021-08-14 - 2028-08-14 (Predicted)
    phase2: 2028-08-14 - 2031-01-01

(Seems to be missing 6.1)

Questions I'd liked answered:

1. How to use CIP kernels. The user-manual mentions Debian a lot, so I'm wondering if there's a way to switch your kernel to the CIP one?
2. What's the CVE parity of the project, compared to other efforts, or via currently supported stable branches. https://gitlab.com/cip-project/cip-kernel/cip-kernel-sec probably answers it, but it requires a lot of work.

+1 for using extendedSupport to document SLTS.