lockdep_ass...cu_read_lock(9)

💅 lockdep_ass...cu_read_lock(9) 💅

ok so bestie, you've wandered into the Kernel API Manual and landed on lockdep_ass...cu_read_lock(9) — the truncated little icon whose full government name is way too long for one line. pull up a chair 🎀

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✨ NAME ✨

lockdep_assert_in_rcu_read_lock — the vibe check that goes WARN if not protected by rcu_read_lock() 😤

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✨ SYNOPSIS ✨

lockdep_assert_in_rcu_read_lock

that's it. no args, no flags, no drama. she's a bare, argument-free queen 👑

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✨ DESCRIPTION ✨

so here's the tea, bestie 🍵 — she splats if lockdep is enabled and there's no rcu_read_lock in effect.

"splats" meaning: loud, unignorable, exactly-what-it-sounds-like. this is not a subtle hint, this is the kernel screaming at you in the group chat 💀

heads up: the splat only happens when lockdep is actually enabled — that's the condition, so don't act surprised when a non-lockdep build stays quiet. lockdep covered, rcu_read_lock in effect — that's the checklist, no cap ✨

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✨ SEE ALSO ✨

the whole RCU friend group showed up to the party and honestly? iconic. every single one, in the order they were invited 🫶 the kernel file is ./include/linux/rcupdate.h, and these are all (9) pages:

• same_state_synchronize_rcu(9)
• cond_resched_tasks_rcu_qs(9)
• rcu_softirq_qs_periodic(9)
• RCU_LOCKDEP_WARN(9)
• lockdep_assert_in_rcu_read_lock_bh(9)
• lockdep_assert_in_rcu_read_lock_sched(9)
• lockdep_assert_in_rcu_reader(9)
• unrcu_pointer(9)
• RCU_INITIALIZER(9)
• rcu_assign_pointer(9)
• rcu_replace_pointer(9)
• rcu_access_pointer(9)
• rcu_dereference_check(9)
• rcu_dereference_bh_check(9)
• rcu_dereference_sched_check(9)
• rcu_dereference_all_check(9)
• rcu_dereference_protected(9)
• rcu_dereference(9)
• rcu_dereference_bh(9)
• rcu_dereference_sched(9)
• rcu_dereference_all(9)
• rcu_pointer_handoff(9)
• rcu_read_lock(9)
• rcu_read_unlock(9)
• rcu_read_lock_bh(9)
• rcu_read_unlock_bh(9)
• rcu_read_lock_sched(9)
• rcu_read_unlock_sched(9)
• RCU_INIT_POINTER(9)
• RCU_POINTER_INITIALIZER(9)
• kfree_rcu(9)
• kfree_rcu_mightsleep(9)
• kfree_rcu_nolock(9)
• rcu_head_init(9)
• rcu_head_after_call_rcu(9)

like, thirty-five relatives at one dinner table. and every single one made it onto the list — no cutting the cousins 💜

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mwah, that's the whole page. short, sweet, and fully locked down 🦋

this little moment came to you from ./include/linux, dated October 2026, and it's still filed under lockdep_ass...cu_read_lock(9) — truncated name and all. love that for her. bye bestie! 💖✨🎀