hrtimer_start_range_ns_user(9)

💖 hrtimer_start_range_ns_user(9) 💖

okay so bestie, welcome to the Kernel API Manual ✨ this one's all about hrtimer_start_range_ns_user — the (re)start of a user-controlled hrtimer, and honestly it's giving main character energy in ./kernel/time/hrtimer.c 🎀

---

🌸 NAME 🌸

hrtimer_start_range_ns_user — (re)start an user controlled hrtimer 👑 lowkey iconic, no cap

---

✨ SYNOPSIS ✨

bool hrtimer_start_range_ns_user (struct hrtimer *timer , ktime_t tim ,
u64 delta_ns , const enum hrtimer_mode mode );

fr fr that's the whole vibe — a bool coming back at you 💅

---

🦋 ARGUMENTS 🦋

• timer — the timer to be added 🕰️ like, the actual thing you're queueing up
• tim — expiry time ⏰ when it goes off, bestie
• delta_ns — the "slack" range for the timer 🫶 yes queen, a little wiggle room, quoted in the original and everything
• mode — timer mode, and listen closely because there's lore here 📖:
  • absolute (HRTIMER_MODE_ABS) or relative (HRTIMER_MODE_REL)
  • and pinned (HRTIMER_MODE_PINNED)
  • softirq based mode is considered for debug purpose only! 💀 not me warning you, it literally says that

---

🌈 RETURN 🌈

• True when the timer was queued ✅ slay
• false if it was already expired 😭 awkward but okay

---

💜 DESCRIPTION 💜

okay so this is the important part, don't skip it 🙈 This function cannot invoke the timer callback for expired timers, because it might be called under a lock which the timer callback needs to acquire. so like… deadlock vibes, we don't do that here 💀

So the caller has to handle that case. yes, you. you handle it. periodt 🌟

---

🧚 SEE ALSO 🧚

Kernel file ./kernel/time/hrtimer.c — go read it, it ate 🔥

• hrtimer_update_function(9)
• hrtimer_forward(9)
• hrtimer_start_range_ns(9)
• hrtimer_try_to_cancel(9)
• hrtimer_cancel(9)
• __hrtimer_get_remaining(9)
• hrtimer_get_next_event(9)
• hrtimer_next_event_without(9)
• hrtimer_setup(9)
• hrtimer_setup_on_stack(9)
• hrtimer_sleeper_start_expires(9)
• hrtimer_setup_sleeper_on_stack(9)

---

🫶 quick vibe check bestie: HRTIMER_MODE_ABS / HRTIMER_MODE_REL / HRTIMER_MODE_PINNED are the modes, softirq based mode is debug purpose only, and the callback situation for expired timers is your problem, not the function's ✨

---

and that's the whole page, iykyk 💖 this gem lives in ./kernel/time, dated October 2026, and it's hrtimer_start_range_ns_user(9) — go forth and schedule responsibly 🎀🦋💅