init_rcu_head_on_stack(9)

🦋 init_rcu_head_on_stack 🦋

okay so bestie, this is the Kernel API Manual page for init_rcu_head_on_stack(9) — manual name folded in right here, iconic. It’s all about giving an on-stack rcu_head its debugobjects moment. Slay.

🎀 NAME 🎀

init_rcu_head_on_stack — initialize on-stack rcu_head for debugobjects.

✨ SYNOPSIS ✨

void init_rcu_head_on_stack (struct rcu_head *head );

💅 ARGUMENTS 💅

• head — pointer to rcu_head structure to be initialized. This is the head being handed over, bestie.

🔥 DESCRIPTION 🔥

Okay so here’s the vibe: this function informs debugobjects of a new rcu_head structure that has been allocated as an auto variable on the stack. It’s giving “hey debugobjects, new stack auto variable just dropped.” ✨

This function is not required for rcu_head structures that are statically defined or that are dynamically allocated on the heap. So don’t come for this function unless the head is living that stack life.

lowkey important: this function has no effect for !CONFIG_DEBUG_OBJECTS_RCU_HEAD kernel builds. No cap. 💀

👀 SEE ALSO 👀

The kernel file to peek at is ./kernel/rcu/update.c, and the whole friend group is:

• rcu_read_lock_held_common(9)
• rcu_async_hurry(9)
• rcu_async_relax(9)
• rcu_expedite_gp(9)
• rcu_unexpedite_gp(9)
• rcu_read_lock_held(9)
• rcu_read_lock_bh_held(9)
• wakeme_after_rcu(9)
• destroy_rcu_head_on_stack(9)
• get_completed_synchronize_rcu(9)

mwah 💋 sign-off: source ./kernel/rcu, date October 2026, page init_rcu_head_on_stack(9) — periodt. 🫶