STRUCT IRQENTRY_STATE(9)

💖 struct irqentry_state(9) 💖

okay bestie, we're deep in the Kernel API Manual today and this one is like… a little mystery box of exception state 🎀 yes, the manual name is literally struct irqentry_state(9), welcome to the vibe.

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✨ NAME ✨

struct irqentry_state — the opaque object where exception state goes to be stored 🫶

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🌸 SYNOPSIS 🌸

struct irqentry_state {
    union {
      bool exit_rcu;
      bool lockdep;
    };
 };

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🦋 Members 🦋

• {unnamed_union} — anonymous, no name, iconic behaviour honestly 💅
• exit_rcu — used exclusively in the irqentry_*() calls; it signals whether the exit path has to invoke ct_irq_exit. that's its whole job, no cap.
• lockdep — used exclusively in the irqentry_nmi_*() calls; it makes sure the lockdep state gets restored correctly on exit from nmi. she's got one responsibility and she ate 🔥

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💜 Description 💜

so here's the tea: this opaque object gets filled in by the irqentry_*_enter functions, and it must be passed back into the corresponding irqentry_*_exit functions once the exception is complete. that's the whole flow, no shortcuts 🙈

callers of irqentry_*_[enter|exit]() must treat this structure as opaque and every single member as private. periodt. the member descriptions above are there purely to help with maintaining the irqentry_*() functions — they are not an invitation to go poking around in there, bestie 😭

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/irq-entry-common.h
• arch_enter_from_user_mode(9), arch_in_rcu_eqs(9)
• enter_from_user_mode(9), arch_exit_to_user_mode_work(9)
• arch_exit_to_user_mode_prepare(9), arch_exit_to_user_mode(9)
• arch_do_signal_or_restart(9), __exit_to_user_mode_prepare(9)
• syscall_exit_to_user_mode_prepare(9)
• irqentry_exit_to_user_mode_prepare(9), exit_to_user_mode(9)
• irqentry_enter_from_user_mode(9), irqentry_exit_to_user_mode(9)
• irqentry_enter_from_kernel_mode(9)
• irqentry_exit_to_kernel_mode_preempt(9)
• irqentry_exit_to_kernel_mode_after_preempt(9)
• irqentry_exit_to_kernel_mode(9), irqentry_enter(9), irqentry_exit(9)
• irqentry_nmi_enter(9), irqentry_nmi_exit(9)

ngl that's a whole friend group of (9) pages, go read them all 💀

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anyway bestie, this page lives in ./include/linux, it's dated October 2026, and it's filed under struct irqentry_state(9) in the Kernel API Manual — go off, stay opaque, mwah 💋✨🌈