[RFC] Explicit kernel version requirements? #5113
Description
At the moment we do not have an explicit kernel version requirement for all of runc, which leads us to having to support ancient kernels with workarounds without any clear indication that we actually have users on such old kernels.
We should probably start making our minimum kernel version requirements far more explicit and specify a policy for how it gets bumped (for instance, it can only be bumped in minor releases and must be at least as old as the oldest upstream LTS kernel branch -- though I suspect we might want to be more conservative and require supporting the oldest LTS enterprise kernel from any of the "big players").
For reference, systemd v260 has a minimum kernel version of Linux 5.10. The closest thing we have AFAICS is a mere recommendation to use Linux 5.2 or newer if you use cgroupv2 in docs/cgroup-v2.md.