rcu_dereference_bh_check(9)

💖 NAME 💖

Okay so bestie, this is the Kernel API Manual page for rcu_dereference_bh_check(9) ✨. Official-name vibes: rcu_dereference_bh_check - rcu_dereference_bh with debug checking. That's the whole main-character energy of this page, no cap.

🌸 SYNOPSIS 🌸

rcu_dereference_bh_check (p , c );

🎀 ARGUMENTS 🎀

• p — the pointer to read, prior to dereferencing it. Read first, dereference later, iykyk 💅.
• c — the conditions under which the dereference will take place. Literally the conditions, bestie.

💅 DESCRIPTION 💅

This is the RCU-bh counterpart to rcu_dereference_check. That's the core fact, periodt.

But please note — and this is giving important-plot-twist energy — starting in v5.0 kernels, vanilla RCU grace periods wait for local_bh_disable regions of code in addition to regions of code demarked by rcu_read_lock and rcu_read_unlock. So yeah, the grace periods are doing extra credit now.

This means synchronize_rcu, call_rcu, and friends all take not only rcu_read_lock but also rcu_read_lock_bh into account. They're matching the whole fit, not just one accessory 🫶.

🦋 SEE ALSO 🦋

Kernel file: ./include/linux/rcupdate.h — and here's the whole squad, bestie:

• 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(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_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)

Mwah 💋 — source ./include/linux, date October 2026, page rcu_dereference_bh_check(9). Bye bestie! 🫶