STRUCT KLP_OPS(9)

💖 struct klp_ops (manual section 9, Kernel API Manual, bestie) 💖

okay so welcome to the struct klp_ops glow-up tour ✨ this is a Kernel API Manual page, section 9, and it's literally about a little struct that keeps track of registered ftrace ops structs. she's small, she's iconic, she's holding the whole livepatch function-swap together. let's get into it 💅

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🌸 NAME 🌸

struct klp_ops — structure for tracking registered ftrace ops structs 🫶

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✨ SYNOPSIS ✨

like, here's literally what she looks like, character for character, no cap:

struct klp_ops {
    struct list_head node;
    struct list_head func_stack;
    struct ftrace_ops fops;
};

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🎀 Members 🎀

• node — the node for the global klp_ops list 💫 this is how she links up with all her sisters.
• func_stack — list head for the stack of klp_func's (and the active func is sitting right on top 👑 main character energy fr).
• fops — the registered ftrace_ops struct. that's her whole job honestly.

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🦋 Description 🦋

so the way this works: a single ftrace_ops is shared between all the enabled replacement functions (klp_func structs) that have the same old_func. one ops to rule them all, lowkey efficient 💅

and that sharing is the whole point — it lets the switch between function versions happen instantaneously by just updating the klp_ops struct's func_stack list. no drama, no waiting, just vibes and a pointer update ✨

and who wins? the winner is the klp_func at the top of the func_stack (aka the front of the list). front of the list = front of the line = she ate 💖

ngl the "instantaneous" part is doing a lot of heavy lifting here and it's genuinely the slay of the whole design, ok?

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🌈 SEE ALSO 🌈

• Kernel file ./kernel/livepatch/patch.h — go read it, iykyk 📖

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and that's the whole page bestie, hope you took notes 🍓 this was ./kernel/livepatch, October 2026, struct klp_ops(9) — mwah, study hard, drink water, and may all your lists stay correctly headed 💜🧚‍♀️