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Live Patching Now Available For Linux

Posted by timothy on from the not-big-and-fancy dept.

New submitter cyranix writes "You may never have to reboot your Linux machine ever again, even for kernel patching," and excerpts from the long (and nicely human-readable) description of newly merged kernel code that does what Ksplice has for quite a while (namely, offer live updating for Linux systems, no downtime required), but without Oracle's control. It provides a basic infrastructure for function "live patching" (i.e. code redirection), including API for kernel modules containing the actual patches, and API/ABI for userspace to be able to operate on the patches (look up what patches are applied, enable/disable them, etc). It's relatively simple and minimalistic, as it's making use of existing kernel infrastructure (namely ftrace) as much as possible. It's also self-contained, in a sense that it doesn't hook itself in any other kernel subsystem (it doesn't even touch any other code). It's now implemented for x86 only as a reference architecture, but support for powerpc, s390 and arm is already in the works (adding arch-specific support basically boils down to teaching ftrace about regs-saving).

7 of 117 comments (clear)

  1. No more downtime by ArcadeMan · · Score: 5, Funny

    Which means you can keep it up forever!

    (PHRASING!)

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  2. Reboot for Systemd by Anonymous Coward · · Score: 3, Funny

    Yup. Exactly.

    But then I guess the quest for epic uptime is bogus, right? Who the heck would want their system running 24/7 all the time?

    *waits for Systemd flamewar to break out*

  3. Time to update the ol' t-shirt... by DigitAl56K · · Score: 5, Funny

    ... to a more extreme version:

    "I don't always test my code, but when I do it's via live patching the kernel on production"

  4. Doesn't hook itself in any other kernel subsystem? by Anonymous Coward · · Score: 3, Funny

    Is this the anti-systemd?

  5. Re:Sounds great by bill_mcgonigle · · Score: 4, Funny

    I can't possibly see this ever causing a problem with this because linux is very secure and there is absolutely no way for a malicious user to get elevated access on anything that runs linux. This includes android phones, which are totally invulnerable to hacking.

    You should suggest to Linus that he make kernel features configurable so people can do different builds for different targets. Put it in a dot-config file or something. Maybe in a future release...

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  6. Re: Sounds great by Anonymous Coward · · Score: 2, Funny

    But I'm a professional Starcraft player. The lag of USB packet overhead is killing me!

  7. Obligatory Snark by _bug_ · · Score: 1, Funny

    This is awesome. Now that live patching is part of the kernel I expect it to be implemented in systemd very soon and all my GNU/systemd servers will never need a three finger salute again!