Re: [PATCH] updated preempt-kernel

[Robert Love]

On Sun, 2001-10-21 at 11:24, Andrew Morton wrote:
> This one has been reported before.

Colin, can you try Andrew's patch and report back?  This problem has
been reported before -- its a tty bug that preempt (and SMP I wager)
just aggravate.  I have a patch that I know fixes it, but Andrew's is
_much_ simpler.  I will send you that if this fails.  Please let me
know.

> --- linux-2.4.12-ac3/drivers/char/console.c	Mon Oct 15 16:04:23 2001
> +++ ac/drivers/char/console.c	Sun Oct 21 08:19:42 2001
> @@ -2387,9 +2387,15 @@ static void con_flush_chars(struct tty_s
>  		return;
>  
>  	pm_access(pm_con);
> -	acquire_console_sem();
> -	set_cursor(vt->vc_num);
> -	release_console_sem();
> +	if (vt) {
> +		/*
> +		 * If we raced with con_close(), `vt' may be null.
> +		 * Hence this bandaid.   - akpm
> +		 */
> +		acquire_console_sem();
> +		set_cursor(vt->vc_num);
> +		release_console_sem();
> +	}
>  }
>  
>  /*

	Robert Love