register_pernet_device(9)

💅 register_pernet_device(9) — the Kernel API Manual glow-up ✨

okay so bestie, welcome to the register_pernet_device(9) page from the Kernel API Manual. yes it's a real manpage, yes it's about network namespaces, and yes we're gonna make it make sense. sit down, grab a lil drink 🍓

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🌸 NAME 🌸

register_pernet_device — literally registers a network namespace device. that's the whole vibe. no cap.

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✨ SYNOPSIS ✨

int register_pernet_device (struct pernet_operations *ops );

it returns an int, it takes one pointer, and it's gonna be iconic 🔥

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🎀 ARGUMENTS 🎀

• ops — the pernet operations structure for the subsystem. that's it, that's the whole argument. it's giving "one job, doing it well" 💅

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🦋 DESCRIPTION 🦋

so what this does is register a device that has init and exit functions, and those get called when network namespaces are created and destroyed respectively. created → init, destroyed → exit. cute, clean, symmetric 🫶

when you register, all the network namespace init functions are called for every existing network namespace. the whole point? it lets kernel modules have a race free view of the set of network namespaces. no races, no drama, no "wait did that namespace exist yet" meltdowns. we love a consistent snapshot ✨

when a new network namespace is created, all of the init methods are called in the order in which they were registered. first come, first called. very main character, very orderly 👑

when a network namespace is destroyed, all of the exit methods are called in the reverse of the order with which they were registered. yes bestie, last in, first out — cleanup unwinds the exact opposite way it wound up. it's giving stack energy and honestly? iconic 🧚

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🌈 SEE ALSO 🌈

• the kernel file ./net/core/net_namespace.c (go read it, iykyk)
• net_ns_get_ownership(9)
• net_ns_barrier(9)
• get_net_ns(9)
• register_pernet_subsys(9)
• unregister_pernet_subsys(9)
• unregister_pernet_device(9)

like, if you're registering devices you probably also wanna know about unregistering them. just saying 😭

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real talk tho: keep the order rules in mind fr fr — init goes registration order, exit goes reverse registration order. that's the whole personality of this function and you don't wanna fumble it 💀

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and that's the page!! slay 💖 this lil masterpiece lives at ./net/core, dated October 2026, and it answers to the name register_pernet_device(9) if you ever need to find it again. mwah 🎀✨