STRUCT NBCON_STATE(9)

💅 struct nbcon_state(9) — the vibe check on nbcon console state

okay bestie, welcome to the Kernel API Manual ✨ this one's short and sweet, so grab your iced coffee 🍓

🌸 NAME 🌸

struct nbcon_state — console state for nbcon consoles. that's it, that's the whole name. iconic brevity 💅

🎀 SYNOPSIS 🎀

like, here's the actual struct, copied character for character because we do not mess with the source 🫶

       struct nbcon_state {
           union {
             unsigned int    atom;
             struct {
               unsigned int prio               :  2;
               unsigned int req_prio           :  2;
               unsigned int unsafe             :  1;
               unsigned int unsafe_takeover    :  1;
               unsigned int cpu                : 24;
             };
           };
        };

✨ Members ✨

okay so this is where it gets juicy, let's go through every single one because we don't skip 💖

• {unnamed_union} — anonymous. yes babe, it has no name, it's mysterious like that 🙈
• atom — the compound of the state fields, made for atomic operations. so you can grab the whole thing in one shot, no cap 🔥
• {unnamed_struct} — also anonymous. two anonymous things in one struct, it's giving main character energy 👑
• prio — the priority of the current owner. the real one, the one actually holding it 💅
• req_prio — the priority of a handover request. like someone politely (or not) asking for the unlock 🫶
• unsafe — console is busy in a non takeover region. lowkey do NOT touch this one 😭
• unsafe_takeover — a hostile takeover in an unsafe state happened in the past. the console cannot be safe until re-initialized. fr fr, this is a permanent scar until you re-init 💀
• cpu — the CPU on which the owner runs. 24 bits of "who's your CPU bestie" 🌈

🦋 Description 🦋

so what's this struct for? it's to be used for reading and preparing of the value stored in the nbcon state variable console::nbcon_state. that's the whole job, and it slays at it ✨

now here's the important bit, ngl — the prio and req_prio fields are particularly important. why? because they allow spin-waiting to timeout and give up without the risk of a waiter being assigned the lock after giving up. like, no phantom lock handoff, none of that chaos. that's the whole reason these fields exist and they ate 💅🔥

🧚 SEE ALSO 🧚

go read these next, i promise they're worth it:

• Kernel file ./include/linux/console.h
• struct consw(9)
• enum cons_flags(9)
• enum nbcon_prio(9)
• struct nbcon_context(9)
• struct nbcon_write_context(9)
• struct console(9)
• console_srcu_read_flags(9)
• console_srcu_write_flags(9)
• for_each_console_srcu(9)
• for_each_console(9)

and that's the page bestie!! 🎀 brought to you from ./include/linux, dated October 2026, in the Kernel API Manual — struct nbcon_state(9) out, mwah 💋💖