= Linux kernel sysctl support =

This is an informal wiki to keep tabs on Linux kernel proc sysctl support ongoing R&D and outstanding things.

<<TableOfContents(2)>>

= Current development =

Things requiring more community eyeballs or maintainer review:

  * Adding const qualifier to static ctl_table arrays:
    Thomas Weißschuh is pushing this forward

  * removing ctl_table array sentinel
    The subsystems that are done are arch/, drivers/, fs/, kernel/, mm/, io_uring/, net/
    Outstanding are w things: 1. Making sure that we remove sentinels that have been added in resent releases and 2. Remove the check for proc_name == NULL (This is set for 6.11).

= History =

This contains the list of changes sent to Linus, this is a summary, you can get the full details with `git log --merges  --grep="Pull sysctl"`.

== 2024 ==
* Fix the check-sysctl-docs. Take care of the false positives, more [[https://lore.kernel.org/all/20240223095918.karsamdx3a2w3v7w@joelS2.panther.com|check-sysctl-docs]]

== 2023 ==
Joel Granados has stepped up to do the major work on removal of the extra empty sentinel for sysctls, saving us about 64 bytes per array and no more bloating when we move sysctls out from `kernel/sysctl.c` to its own subsystem. We expect full removal of the sentinel by v6.8-rc1.

  * [[https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=426ee5196d1821d70192923e70c0f8347faade47|sysctl-v6.7-rc1]] - 2023-11-01
  * [[https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=adfd671676c922bada16477eb68b5eb5f065addc|sysctl-v6.6-rc1]] - 2023-08-29

= TODO =
  * remove kernel/sysctl.c kitchen sink
  * extend kdevops sysctl testing with kunit sysctl support, it already has selftests support
  * connect with patchwork as eBPF folks have done for certain patches
  * hookup kdeovps sysctl testing with 0-day