linux-kernel - Re: printk's threaded legacy console + fbcon => schedule where it should not

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Message-ID: <20260120110845.2922a91a@gandalf.local.home>
Date: Tue, 20 Jan 2026 11:08:45 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
 linux-fbdev@...r.kernel.org, Petr Mladek <pmladek@...e.com>, John Ogness
 <john.ogness@...utronix.de>, Sergey Senozhatsky <senozhatsky@...omium.org>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Jiri Slaby
 <jirislaby@...nel.org>, Simona Vetter <simona@...ll.ch>, Helge Deller
 <deller@....de>
Subject: Re: printk's threaded legacy console + fbcon => schedule where it
 should not

On Wed, 14 Jan 2026 15:59:55 +0100
Sebastian Andrzej Siewior <bigeasy@...utronix.de> wrote:

> @@ -3362,22 +3362,6 @@ void console_unlock(void)
>  }
>  EXPORT_SYMBOL(console_unlock);
>  
> -/**
> - * console_conditional_schedule - yield the CPU if required

Egad! That goes all the way back to 2002:

  https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=a880f45a48be2956d2c78a839c472287d54435c1

> - *
> - * If the console code is currently allowed to sleep, and
> - * if this CPU should yield the CPU to another task, do
> - * so here.
> - *
> - * Must be called within console_lock();.
> - */
> -void __sched console_conditional_schedule(void)
> -{
> -	if (console_may_schedule)
> -		cond_resched();
> -}
> -EXPORT_SYMBOL(console_conditional_schedule);

I'm assuming this likely isn't needed anymore. I don't know of any reason
it needs to stay.

Should we just remove it and see what breaks?

-- Steve



> -
>  void console_unblank(void)
>  {
>  	bool found_unblank = false;