Linux 5.5 Livepatching Tracks The System State For Better Patch Handling/Compatibility

The kernel livepatching infrastructure that allows applying kernel patches (primarily security fixes) to a running kernel without the need to reboot in order to avoid downtime is seeing a big improvement with Linux 5.5.

With the Linux 5.5 livepatching support comes system state tracking in order to better handle different kernel live patches over time that could potentially clash with one another. Patches altering shadow variables and callbacks could lead to cases where live-patches cannot be reverted easily or not jive with future live-patches, but the system state tracking is designed to track those state changes so there is the ability to revert complex patches later on.

The Linux 5.5 livepatching documentation explains the system state tracking in more detail.

That new API was the main change of the pull request but there is also various other code improvements for this increasingly used infrastructure by enterprise Linux distributions.