tty ldisc: Close/Reopen race prevention should check the proper flag

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@liveu.tv>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index ba8be396a6215339200c5ff3f79ad34e93489acb..847f7ed7a3ed9d32f186ad533a6dce9a1375992b 100644 (file)
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -659,7 +659,7 @@ 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);