__futex_unqueue(9)

📦 version 7.3.1, in nixpkgs unstable

💅 __futex_unqueue — like, the whole vibe

okay so bestie, welcome to the Kernel API Manual (that's the manual name, iykyk) — this is section 9 and we're talking about one very specific little function. sit down, grab a strawberry 🍓, let's go.

✨ NAME ✨

__futex_unqueue — remove the futex_q from its futex_hash_bucket

that's it. that's the whole job. it takes the futex_q out of the bucket it's sitting in. no cap, it's that simple 💅

🦋 SYNOPSIS 🦋

void __futex_unqueue (struct futex_q *q );

just like that, one argument, void return, no drama 💖

🌸 ARGUMENTS 🌸

  • q — the struct futex_q you want to unqueue. that's the one getting yanked out of the hash bucket, periodt.

👑 DESCRIPTION 👑

okay so here's the part where you actually have to pay attention, bestie, because there's a rule and the rule is not optional 🙈

q->lock_ptr must not be NULL, and it must be held by the caller.

that's it. that's the whole contract. call it with a NULL lock_ptr and it's giving disaster. call it without holding the lock and it's giving ❌ undefined vibe check ❌. so like, hold the lock. it's not a suggestion, it's a requirement, fr fr 🔥

🔥 SEE ALSO 🔥

the whole friend group, honestly 🫶:

and they all live in the kernel file ./kernel/futex/core.c — go say hi, they're iconic 👑

quick lil heads up: futex_unqueue(9) (no underscores up front) and our girl __futex_unqueue(9) are both in that list and they are not the same function. don't mix them up bestie, that's a whole different vibe 😭

🎀 okay that's the page!! big slay, you now understand __futex_unqueue better than 90% of people on this planet, lowkey. this came to you from ./kernel/futex, dated October 2026, and it's literally titled __futex_unqueue(9) because of course it is. bye bestie, go hold a lock responsibly 💜✨

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