register_reboot_notifier(9)

✨ register_reboot_notifier(9) — the kernel API manual glow-up ✨

okay so bestie, welcome to the register_reboot_notifier(9) page 💅 this is a Kernel API Manual entry and honestly? it's a little baddie with one job and it does it perfectly 🎀

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🌸 NAME 🌸

register_reboot_notifier — literally just: register a function so it gets called at reboot time ⭐ like, that's the whole vibe. reboot era incoming 🔥

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💖 SYNOPSIS 💖

int register_reboot_notifier (struct notifier_block *nb );

that's it, that's the whole signature, no cap 🫶

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🦋 ARGUMENTS 🦋

• nb — info about the notifier function that's gonna get called 👑 this struct is the whole personality holder: it's where you tell the kernel which function to ring up when reboot o'clock hits 😭

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🧚 DESCRIPTION 🧚

okay so what this does: it registers your function into the list of functions that get called at reboot time 📋✨ so when the machine goes down for its little reboot nap, your function is on the guest list 💌

and here's the iconic part — it currently always returns zero, because blocking_notifier_chain_register always returns zero. so the return value is giving zero, slay, no drama, no surprises 💀✨

lowkey important: this isn't us guessing at behaviour, it's literally in the docs — the "currently" is doing a lot of work there, iykyk 🙈

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🌈 SEE ALSO 🌈

• Kernel file ./kernel/reboot.c
• emergency_restart(9)
• unregister_reboot_notifier(9)
• register_restart_handler(9)
• unregister_restart_handler(9)
• do_kernel_restart(9)
• kernel_restart(9)
• kernel_halt(9)
• register_sys_off_handler(9)
• unregister_sys_off_handler(9)
• devm_register_sys_off_handler(9)
• devm_register_power_off_handler(9)
• devm_register_restart_handler(9)
• register_platform_power_off(9)
• unregister_platform_power_off(9)
• do_kernel_power_off(9)
• kernel_can_power_off(9)
• kernel_power_off(9)
• orderly_poweroff(9)
• orderly_reboot(9)
• hw_failure_emergency_action_func(9)
• hw_failure_emergency_schedule(9)
• __hw_protection_trigger(9)

the way that's a whole friend group of reboot/shutdown besties 😭🫶 go read them all, fr fr.

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and that's the page!! 💜 before you go: this lil masterpiece lives in the ./kernel source tree, it's October 2026 energy, and it's filed as register_reboot_notifier(9) — go forth and be the main character of your own notifier chain 🎀💅✨