register_fprobe_ips(9)

📦 version 7.3.1, in nixpkgs unstable

💅 register_fprobe_ips — Kernel API Manual, section 9 💅

okay so bestie, welcome to register_fprobe_ips(9) — the page that's gonna teach you how to register an fprobe to ftrace by address. yes, address. not symbol. we're being specific today. ✨

🌸 SYNOPSIS 🌸

int register_fprobe_ips (struct fprobe *fp , unsigned long *addrs , int num );

that's it. that's the whole vibe check. three args, one int coming back at you. 🫶

🎀 ARGUMENTS 🎀

  • fp — the fprobe data structure you want to get registered. your little probe baby. 🥺
  • addrs — an array of target function addresses. plural, because yes, you're doing multiple.
  • num — the number of entries in addrs. like, how many addresses you actually put in there. don't lie to it.

🦋 DESCRIPTION 🦋

so what this does is: it registers fp to ftrace so that the probe gets enabled on the addresses you handed over in addrs. simple enough, right? but — and this is the part where you need to pay attention, bestie — those addrs must be the addresses of the ftrace location address, which may be the symbol address + an arch-dependent offset. yes, arch-dependent. meaning it changes per architecture. iykyk. 😭

🚨 if you're sitting here like "wait, i'm not sure what that means" — same, no judgment — then the manpage has a direct instruction for you: please use other registration functions. do not pass go. do not collect $200. go use the other ones. 💀

it returns 0 if fp got registered successfully, and -errno if it did not. so like, zero is the slay outcome. negative errno is the not-slaying outcome. check it. 🔥

👑 SEE ALSO 👑

go look at the kernel file ./kernel/trace/fprobe.c, and also these fellow icons:

⭐ little sign-off ⭐

this page lives in ./kernel/trace, dated October 2026, and it's register_fprobe_ips(9) from the Kernel API Manual — go register some probes responsibly, bestie. mwah. 💖🧚🌈

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