text_poke(9)

💅 text_poke(9) — a Kernel API Manual moment 🎀

okay bestie, this is the text_poke(9) page from the Kernel API Manual — and it's literally about updating instructions on a live kernel. yes, live, as in already running. main character energy, but careful hands. ✨

✨ NAME ✨

text_poke — Update instructions on a live kernel.

🌸 SYNOPSIS 🌸

void * text_poke (void *addr , const void *opcode , size_t len );

🎀 ARGUMENTS 🎀

• addr — address to modify.
• opcode — source of the copy.
• len — length to copy.

🦋 DESCRIPTION 🦋

okay so here's the rule, no cap: when you are not doing early patching, only atomic text poke/set should be allowed. that means the size must be writable atomically, and the address must be aligned in a way that permits an atomic write. it also makes sure we fit on a single page. ✨

also, the caller must ensure that if the modified code is part of a module, the module would not be removed during poking. how do you lock that down? register a module notifier, and order module removal and patching through a mutex. periodt. 🫶

💜 SEE ALSO 💜

• Kernel file ./arch/x86/kernel/alternative.c
• text_poke_early(9)
• text_poke_kgdb(9)
• text_poke_copy(9)
• text_poke_set(9)
• smp_text_poke_batch_finish(9)
• smp_text_poke_batch_add(9)
• smp_text_poke_single(9)

okay that's the whole page, bestie 🫶 source: ./arch/x86/kernel; date: October 2026; page: text_poke(9). byeeee 💅✨