From: John Ogness Date: Mon, 23 Oct 2023 17:43:48 +0000 Subject: [PATCH 34/48] printk: Atomic print in printk context on shutdown Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz For nbcon consoles, normally the printing is handled by the dedicated console printing threads. However, on shutdown the printing threads may not get a chance to print the final messages. When shutting down or rebooting (system_state > SYSTEM_RUNNING), perform atomic printing from the printk() caller context. Signed-off-by: John Ogness Signed-off-by: Sebastian Andrzej Siewior --- kernel/printk/printk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2402,12 +2402,17 @@ asmlinkage int vprintk_emit(int facility * * - When this CPU is in panic. * + * - During shutdown, since the printing threads may not get + * a chance to print the final messages. + * * Note that if boot consoles are registered, the console * lock/unlock dance must be relied upon instead because nbcon * consoles cannot print simultaneously with boot consoles. */ - if (is_panic_context) + if (is_panic_context || + (system_state > SYSTEM_RUNNING)) { nbcon_atomic_flush_pending(); + } } if (do_trylock_unlock) {