rcu_dereference_sched_check(9)

💖 rcu_dereference_sched_check(9) 💖

okay bestie, this one is straight from the Kernel API Manual, and it is literally rcu_dereference_sched with debug checking. Buckle up, it’s giving “tiny page, important RCU lore.” 🎀

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✨ NAME ✨

rcu_dereference_sched_check — it’s rcu_dereference_sched with debug checking, periodt. 💅

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🎀 SYNOPSIS 🎀

rcu_dereference_sched_check (p , c );

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🫶 ARGUMENTS 🫶

• p — the pointer to read, prior to dereferencing. Like, look first, bestie, do not just dive in. 👀
• c — the conditions under which the dereference will take place. It’s the vibe check for your dereference, iykyk. ✨

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🔥 DESCRIPTION 🔥

This is the RCU-sched counterpart to rcu_dereference_check. Big sibling energy fr fr. 🫶

However, please note that starting in v5.0 kernels, vanilla RCU grace periods wait for preempt_disable regions of code in addition to regions of code demarked by rcu_read_lock and rcu_read_unlock. The way that changes things: this means that synchronize_rcu, call_rcu, and friends all take not only rcu_read_lock but also rcu_read_lock_sched into account. No cap. 💀🔥

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🌈 SEE ALSO 🌈

Kernel file ./include/linux/rcupdate.h — and the whole “linked list of friends” situation:

• 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_bh_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)

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mwah 💋 that’s the whole page, bestie — cute little sign-off: source/version corner is ./include/linux, dated October 2026, and yes, the page is rcu_dereference_sched_check(9). 🎀✨🦋