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Subject[PATCH 4.18 34/44] tty: Drop tty->count on tty_reopen() failure
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dmitry Safonov <dima@arista.com>

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@vger.kernel.org # v4.6+
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Jiri Slaby <jslaby@suse.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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
@@ -1264,6 +1264,7 @@ 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)
@@ -1277,10 +1278,14 @@ 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;
}

/**

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