Re: Subject: [PATCH] tty ldisc: Close/Reopen race prevention shouldcheck the proper flag

[Shachar Shemesh]

On 07/07/2012 12:24 AM, Greg KH wrote:
> On Sun, Jul 01, 2012 at 09:53:19AM +0300, Shachar Shemesh wrote:
> > From: Shachar Shemesh <shachar@xxxxxxxx>
> >
> > Commit acfa747b introduced the TTY_HUPPING flag to distinguish
> > closed TTY from currently closing ones. The test in tty_set_ldisc
> > still remained pointing at the old flag. This causes pppd to
> > sometimes lapse into uninterruptible sleep when killed and
> > restarted.
> >
> > Signed-off-by: Shachar Shemesh <shachar@xxxxxxxx>
> > ---
> > Tested with 3.2.20 kernel.
> All tabs are converted to spaces and make this patch impossible to apply
> :(
>
> Care to try again?
I'm sorry, I'm sending this as an attachment. I've verified that my 
mailer sends this as plain text, so it should be okay.

Shachar

diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 24b95db..a662a24 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -658,7 +658,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 		goto enable;
 	}
 
-	if (test_bit(TTY_HUPPED, &tty->flags)) {
+	if (test_bit(TTY_HUPPING, &tty->flags)) {
 		/* We were raced by the hangup method. It will have stomped
 		   the ldisc data and closed the ldisc down */
 		clear_bit(TTY_LDISC_CHANGING, &tty->flags);