debug_set_critical(9)

💅 debug_set_critical(9) — the "don't spin, just try" era

okay so bestie, welcome to the Kernel API Manual, section 9 — yes, the kernel API manual, we're in the big leagues now 🎀. This page is all about debug_set_critical, and ngl it's a tiny function with a very specific job. Let's get into it ✨

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🌸 NAME 🌸

debug_set_critical — event/exception functions try lock instead of spin. that's the whole vibe, fr fr 💅

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🦋 SYNOPSIS 🦋

void debug_set_critical (void );

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🎀 ARGUMENTS 🎀

• void — no arguments. none. zero. the void is voiding 🫶

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⭐ RETURN ⭐

• none

like, literally nothing comes back. it's giving "I did the thing and left" 😭

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💖 DESCRIPTION 💖

So here's the tea ☕ — right now this is used in the case of stopping all CPUs but the current one. Once you're in that state, the functions that write a debug entry for an event or an exception no longer spin on the debug area lock. Instead they only try to get it, and if they don't get the lock, they just fail. no waiting, no spinning, no hanging around the lock like it's a group chat you weren't invited to 🙈

tl;dr: spin → try. that's the whole character arc 👑

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🧚 SEE ALSO 🧚

the kernel file ./arch/s390/kernel/debug.c is the main character here, and these are the friends in its group chat:

• debug_next_entry(9)
• debug_to_act_entry(9)
• debug_prev_entry(9)
• debug_move_entry(9)
• debug_dump(9)
• debug_register_mode(9)
• debug_register(9)
• debug_register_static(9)
• debug_unregister(9)
• debug_set_level(9)
• debug_stop_all(9)
• debug_register_view(9)
• debug_unregister_view(9)

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lowkey a whole squad. go read them, iykyk 💀✨

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this page came from ./arch/s390/kernel, dated October 2026 — stay critical, bestie, and don't spin on anything that doesn't deserve it 🦋💜