Re: [Regression] kdesu broken

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

On Sat, Jul 25, 2009 at 03:05:10PM +0100, Alan Cox wrote:
> Actually try this:
> 
> 
> commit b0e6bdde87725a5d46273ecc4bd00c54bd675848
> Author: Alan Cox <alan@linux.intel.com>
> Date:   Sat Jul 25 15:00:04 2009 +0100
> 
>     pty: ensure writes hit the reader before close
>     
>     This is elegant in all the wrong ways. Put the pty into low latency mode (which
>     we can do as we always post bytes from user context). The tty_flip_buffer_push
>     then always calls into the ldisc which means we clear the ldisc buffer before
>     we set the TTY_OTHER_CLOSED flag.
>     
>     Means pty has subtle knowledge of tty internals we really don't want it to, but
>     it fixes the problem for the moment.
>     
>     Signed-off-by: Alan Cox <alan@linux.intel.com>
> 
> diff --git a/drivers/char/pty.c b/drivers/char/pty.c
> index 6e6942c..87d729b 100644
> --- a/drivers/char/pty.c
> +++ b/drivers/char/pty.c
> @@ -47,10 +47,12 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
>  	}
>  	wake_up_interruptible(&tty->read_wait);
>  	wake_up_interruptible(&tty->write_wait);
> +	
>  	tty->packet = 0;
>  	if (!tty->link)
>  		return;
>  	tty->link->packet = 0;
> +	tty_flip_buffer_push(tty->link);
>  	set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
>  	wake_up_interruptible(&tty->link->read_wait);
>  	wake_up_interruptible(&tty->link->write_wait);
> @@ -207,6 +209,7 @@ static int pty_open(struct tty_struct *tty, struct file *filp)
>  	clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
>  	set_bit(TTY_THROTTLED, &tty->flags);
>  	retval = 0;
> +	tty->low_latency = 1;
>  out:
>  	return retval;
>  }

This one fixes "the compile in emacs bug" for me.

http://bugzilla.kernel.org/show_bug.cgi?id=13815

-aneesh