futex_unqueue(9)

💖 futex_unqueue(9) — Kernel API Manual energy 💖

✨ NAME ✨

futex_unqueue — remove the futex_q from its futex_hash_bucket. That’s the whole assignment, bestie 💅

🌸 SYNOPSIS 🌸

int futex_unqueue (struct futex_q *q );

🦋 ARGUMENTS 🦋

• q — the futex_q to unqueue. That’s it. That’s the argument. Slay 🎀

💅 DESCRIPTION 💅

Okay so here’s the part where you gotta pay attention, bestie: q->lock_ptr must not be held by the caller. No cap, that’s important. 🔥

A call to futex_unqueue must be paired with exactly one earlier call to futex_queue. Like, one-to-one, matching-set, no extra copies, periodt. ✨

🚨 Not me being dramatic, but fr fr: don’t hold q->lock_ptr when you call this, and don’t forget the matching earlier futex_queue call. That pairing rule is the vibe check.

🎀 RETURN 🎀

• 1 — if the futex_q was still queued (and we removed unqueued it); 💖
• 0 — if the futex_q was already removed by the waking thread. 🦋

🌈 SEE ALSO 🌈

Kernel file ./kernel/futex/core.c: __futex_hash(9), futex_setup_timer(9), get_futex_key(9), fault_in_user_writeable(9), futex_top_waiter(9), wait_for_owner_exiting(9), __futex_unqueue(9), futex_exit_recursive(9).

xoxo bestie — source/version: ./kernel/futex; date: October 2026 💖🎀✨