Hi Federico! > I'm a CERN employee currently evaluating Debian as a possible solution for our > systems in use to control particle accelerators. I would like to know more > about > how the Debian community handles the Linux kernel integration. In particular, > I > can't easily find the following information:
Cool, if you have more specific followup questions, don't hesitate to ask. > - Criteria to select a kernel version for a Debian release. It looks to me you > are following LTS releases, but as you know kernel LTS is a moving target > in > terms of duration. So, how you choose? Debian releases happen every two years at approximately the end of the second quarter of uneven years. kernel.org LTS releases are usually announced/picked by end of each calendar year and the latest kernel.org LTS gets picked as the kernel version for Debian. Debian 9 has 4.9.x, Debian 10 had 4.19.x, Debian 11 and 5.10 and Debian 12 will have 6.1. > - How much a Debian kernel diverges from kernel.org release overtime? Not much, you can have a look yourself for the current patches applied to the 6.1.27 kernel which will be part of the initial Debian 12 release (and future updates will rebase to 6.1.x LTS releases): https://salsa.debian.org/kernel-team/linux/-/tree/sid/debian/patches Anything in bugfix are cherrypicked bugfixes, debian/ contains a small set of Debian-specific patches (for narrow toolchain or software freedom issues) and feature contains a small set of backports (e.g. currently for improved support for some non-x86 systems). In the past that also included backported support for some NICs or RAID controllers (but these usually only appear later in a release cycle). > - I see you explain how to build and run any kernel from kernel.org, but I do > not see and discouragement in doing so. Is this because you do not see any > known incompatibilities ? Generally running a patched or bespoke kernel is supported. It's mostly a matter of people power to do it properly (since one needs to rebase to security updates and applying custom patches might need rebases if underlying kernel code for updated). Some parts of the OS (e.g. systemd) expectsa given set of kernel features to be present to operate properly, but usually these are quite common and unlikely to be absent in custom configs anyway. If you start with the current Debian kernel config as a base (found under /boot/config-VERSION) you won't run into any surprises. Cheers, Moritz