4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dmitry Safonov <dima@xxxxxxxxxx>
commit fe32416790093b31364c08395727de17ec96ace1 upstream.
In case of tty_ldisc_reinit() failure, tty->count should be decremented
back, otherwise we will never release_tty().
Tetsuo reported that it fixes noisy warnings on tty release like:
pts pts4033: tty_release: tty->count(10529) != (#fd's(7) + #kopen's(0))
Fixes: commit 892d1fa7eaae ("tty: Destroy ldisc instance on hangup")
Cc: stable@xxxxxxxxxxxxxxx # v4.6+
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxxx>
Reviewed-by: Jiri Slaby <jslaby@xxxxxxx>
Tested-by: Jiri Slaby <jslaby@xxxxxxxx>
Tested-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/tty_io.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1475,6 +1475,7 @@ static void tty_driver_remove_tty(struct
static int tty_reopen(struct tty_struct *tty)
{
struct tty_driver *driver = tty->driver;
+ int retval;
if (driver->type == TTY_DRIVER_TYPE_PTY &&
driver->subtype == PTY_TYPE_MASTER)
@@ -1488,10 +1489,14 @@ static int tty_reopen(struct tty_struct
tty->count++;
- if (!tty->ldisc)
- return tty_ldisc_reinit(tty, tty->termios.c_line);
+ if (tty->ldisc)
+ return 0;
- return 0;
+ retval = tty_ldisc_reinit(tty, tty->termios.c_line);
+ if (retval)
+ tty->count--;
+
+ return retval;
}
/**
