stop_one_cpu(9)

okay so bestie, we're in the Kernel API Manual and this whole page is about stop_one_cpu(9) — yes, the one that stops a cpu 🛑✨ buckle up.

💖 NAME 💖

stop_one_cpu — stop a cpu 🛑👑

🎀 SYNOPSIS 🎀

int stop_one_cpu (unsigned int cpu , cpu_stop_fn_t fn , void *arg );

🌸 ARGUMENTS 🌸

• cpu — the cpu to stop 🛑
• fn — the function to execute ✨
• arg — the argument passed to fn 🎁

🦋 DESCRIPTION 🦋

So basically: execute fn(arg) on cpu 💅. fn runs in a process context, at the highest priority, preempting any task on the cpu and straight-up monopolizing it 👑. This function returns after the execution is complete, periodt.

⚠️ Important vibe check: this function does not guarantee that cpu stays online till fn completes. If cpu goes down in the middle, execution may happen partially or fully on different cpus 😭. So fn should either be ready for that, or the caller should make sure cpu stays online until this function completes. no cap.

😴 CONTEXT 😴

Might sleep. literally allowed to snooze 💤

💫 RETURN 💫

• -ENOENT if fn(arg) was not executed because cpu was offline 😬
• otherwise, the return value of fn 🫶

🔥 SEE ALSO 🔥

Kernel file ./kernel/stop_machine.c — go peek bestie 👀. Also check out stop_two_cpus(9), stop_one_cpu_nowait(9), stop_cpus(9), and stop_machine_from_inactive_cpu(9) 🌈

source/version: ./kernel · date: October 2026 · page: stop_one_cpu(9) — byeee bestie, go stop a cpu responsibly 💅✨🎀