Re: [BUG] printk/nbcon.c: watchdog BUG: softlockup - CPU#x stuck for 78s

From: Sebastian Andrzej Siewior
Date: Thu Jun 20 2024 - 05:32:59 EST


On 2024-06-20 09:15:45 [+0200], To Derek Barbosa wrote:
> On 2024-06-18 13:37:42 [-0400], Derek Barbosa wrote:
> > Hi,
> Hi,
>
> > We have a modicum of reasonable suspicion to believe that nbcon_reacquire, or
> > some other nbcon mechanism *may* be causing such behavior.
>
> Does this help?
>
> diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
> index bb9689f94d302..0813ce88a49c5 100644
> --- a/kernel/printk/nbcon.c
> +++ b/kernel/printk/nbcon.c
> @@ -1119,6 +1119,7 @@ static int nbcon_kthread_func(void *__console)
> }
>
> console_srcu_read_unlock(cookie);
> + cond_resched();
>
> } while (backlog);
>

Okay. Works here on a 144 CPU box without CONFIG_PREEMPT.

Sebastian