STRUCT COREDUMP_ACK(9)

💅 struct coredump_ack(9) — from the Kernel API Manual, bestie 💅

okay so real talk, this page is about struct coredump_ack, and yes it lives in the kernel API manual, we love a glow-up ✨

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🎀 NAME 🎀

struct coredump_ack — the lil message that userspace sends to the kernel 🫶 (yes, userspace talks back, it's giving main character energy)

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🌸 SYNOPSIS 🌸

struct coredump_ack {
    __u32 size;
    __u32 spare;
    __u64 mask;
 };

look at her, iconic, three whole members, no notes 💅

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🦋 Members 🦋

• size — literally just the size of the struct, that's it, that's the whole job 💖
• spare — unused, lowkey just vibing there, doing absolutely nothing, respect 🙈
• mask — the features the kernel is supposed to use, like a little wishlist of what you want 🎀

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🌈 Description 🌈

okay so the size member must be set to the size of struct coredump_ack. no cap. and it may never exceed what the kernel returned in coredump_req->size_ack — like, that's the ceiling, bestie ✋ but it may of course be smaller, as long as it's >= COREDUMP_ACK_SIZE_VER0 and <= coredump_req->size_ack. it's giving "you can be smaller but you cannot come for the queen" 👑

the mask member must be set to the features the coredump server wants the kernel to use. and here's the vibe check: only bits the kernel returned in coredump_req->mask may be set. don't be out here setting bits the kernel didn't hand you, that's not the move 😭🔥

fr fr, those two constraints are not suggestions, they're the whole assignment. get them wrong and the kernel is not gonna be chill about it 💀

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⭐ SEE ALSO ⭐

• Kernel file ./tools/include/uapi/linux/coredump.h 💜
• struct coredump_req(9) — her sibling, the request side of the convo 🫶
• enum coredump_mark(9) — the enum bestie, go say hi 🌸

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and that's the page!! 🧚 from ./tools/include/uapi/linux, dated October 2026 — slay, periodt, go read coredump.h and stay hydrated 💖✨🍓