wake_up_pollfree(9)

💅 wake_up_pollfree — a Kernel API Manual moment (section 9, bestie)

okay so this one is from the Kernel API Manual, section 9, and it's genuinely such a niche little icon. like, nobody knows her, but the people who know her know her, iykyk. 🎀

---

✨ NAME ✨

wake_up_pollfree — the function that's literally like "hey bestie, this polled waitqueue is leaving the party, say your goodbyes" 💌

---

🦋 SYNOPSIS 🦋

void wake_up_pollfree (struct wait_queue_head *wq_head );

one function, one pointer, no drama.

---

🌸 ARGUMENTS 🌸

• wq_head — the wait queue head. that's it. that's the whole personality. the wait queue head in question, the main character of this argument list 👑

---

💖 DESCRIPTION 💖

okay so picture this: in the very rare cases (like, very rare, we're talking "you will probably never touch this in your whole kernel career" rare 🙈) where a ->poll implementation uses a waitqueue whose lifetime is tied to a task instead of the struct file being polled — you have to call this function before the waitqueue gets freed. why? bc otherwise the non-blocking polls (think epoll, the girlies who poll without blocking ✨) never find out that the queue is going away. and that's rude. and also a bug. 😭

the vibe check: call wake_up_pollfree first, free after. not the other way around, bestie, i'm begging 🫶

and there's a whole second requirement, no cap: the caller must also RCU-delay the freeing of the wait_queue_head. like, how? any of these ways, pick your slay:

• an explicit synchronize_rcu
• or call_rcu
• or SLAB_TYPESAFE_BY_RCU

that's not optional, that's not a suggestion, that's the rules. ⭐

---

🔥 SEE ALSO 🔥

buckle up bestie, this list is long — the whole waitqueue friend group showed up to the function. 💀

• Kernel file ./include/linux/wait.h waitqueue_active(9)
• wq_has_single_sleeper(9)
• wq_has_sleeper(9)
• wait_event(9)
• wait_event_freezable(9)
• wait_event_timeout(9)
• wait_event_cmd(9)
• wait_event_interruptible(9)
• wait_event_interruptible_timeout(9)
• wait_event_hrtimeout(9)
• wait_event_interruptible_hrtimeout(9)
• wait_event_idle(9)
• wait_event_idle_exclusive(9)
• wait_event_idle_timeout(9)
• wait_event_idle_exclusive_timeout(9)
• wait_event_interruptible_locked(9)
• wait_event_interruptible_locked_irq(9)
• wait_event_interruptible_exclusive_locked(9)
• wait_event_interruptible_exclusive_locked_irq(9)
• wait_event_killable(9)
• wait_event_state(9)
• wait_event_killable_timeout(9)
• wait_event_lock_irq_cmd(9)
• wait_event_lock_irq(9)
• wait_event_interruptible_lock_irq_cmd(9)
• wait_event_interruptible_lock_irq(9)
• wait_event_interruptible_lock_irq_timeout(9)

like i said. the whole friend group. no one got left out of this SEE ALSO, periodt 🧚

---

okay that's the whole page!! mwah 💋 this one comes from ./include/linux, dated October 2026 — hope you had the most slay time reading about a waitqueue going away, love u, bye 🎀✨