kmsan_memmove(9)

💅 kmsan_memmove(9) — the Kernel API Manual moment

okay so bestie, welcome to kmsan_memmove(9), straight out of the Kernel API Manual (that's the manual name, iykyk 🫶). Lowkey this one's a little helper with main character energy — it just tells KMSAN "hey, a copy happened over here" so the shadow metadata doesn't get left on read. ✨

✨ NAME ✨

kmsan_memmove — Notify KMSAN about a data copy within kernel.

🌸 SYNOPSIS 🌸

void kmsan_memmove (void *to , const void *from , size_t to_copy );

🎀 ARGUMENTS 🎀

• to — destination address in the kernel. that's where the data's going, bestie 💖
• from — source address in the kernel. that's where it's coming from 🦋
• to_copy — -- undescribed -- 😭 fr fr the docs literally did not describe this one. not me exposing the manpage like this. it's giving "we left this as an exercise for the reader". 🙈

💅 DESCRIPTION 💅

So here's the vibe: you call this after you've already hit the non-instrumented version of memmove/memcpy — you know, the kind implemented using assembly code 🔥 — and the whole point is to copy KMSAN's metadata alongside. no cap, that's it. that's the function. it keeps the shadow bookkeeping in sync when the fast hand-written copy path skips the usual instrumentation. iconic, honestly. ⭐

ngl, the "invoked after" part matters — it's a follow-up call, not the copy itself. read the order and slay. 👑

🌈 SEE ALSO 🌈

• Kernel file ./include/linux/kmsan-checks.h
• kmsan_poison_memory(9)
• kmsan_unpoison_memory(9)
• kmsan_check_memory(9)
• kmsan_copy_to_user(9)

all the other KMSAN besties are waiting for you in that header file, go say hi 💜🫶

mwah, that's the whole page 💋 — brought to you by ./include/linux, dated October 2026, from the Kernel API Manual. the way this manpage ate and left zero crumbs. periodt. 🎀💖✨