Live Patching Support Planned For Linux 3.20/4.0 Kernel

It looks like for the Linux 3.20 kernel is when the new kernel live patching technology will be integrated to mainline.

This year there's been kGraft and Kpatch in development as new live kernel patching solutions to reduce downtime when applying maintenance/security updates to the kernel by avoiding system reboots, similar in nature to Ksplice. These solutions were devised independently by Red Hat and SUSE while more recently a unified infrastructure combining both kGraft and Kpatch was proposed. It looks like for Linux 3.20 is when that code will be merged.

It's too late for the live patching code to enter Linux 3.19 and making known the Linux 3.20 merging plans was SUSE Labs' Jiri Kosina asking for the live patching tree to be added to linux-next, the sort of staging area for code planned to be merged into the mainline Linux kernel tree in the releases ahead.

Kosina wrote, "a substantial amount of work has been invested into abstracting 'Live Patching' core functionality out of the already existing implementations, so that further improvements can be built on top of it in incremental steps. The core functionality (which is self-contained) now works and has been Reviewed/Acked by both interested parties (i.e. people working on kPatch and kGraft) and agreed to be a common ground on which further development will happen."

This initial code, per Kosina's message, is planned to see a pull request for Linux 3.20. Though based upon earlier messages by Linus Torvalds, Linux 3.20 might become Linux 4.0 if his talk from 2013 holds true.