Re: [Regression] kdesu broken

From: Aneesh Kumar K.V
Date: Sun Jul 26 2009 - 13:42:30 EST


On Sat, Jul 25, 2009 at 03:05:10PM +0100, Alan Cox wrote:
> Actually try this:
>
>
> commit b0e6bdde87725a5d46273ecc4bd00c54bd675848
> Author: Alan Cox <alan@xxxxxxxxxxxxxxx>
> 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@xxxxxxxxxxxxxxx>
>
> 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
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