4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold <johan@xxxxxxxxxx>
commit 90dbad8cd6efccbdce109d5ef0724f8434a6cdde upstream.
Make sure to hold the tty lock as required when calling tty-driver
close() (e.g. to avoid racing with hangup()).
Note that the serport active flag is currently set under the lock at
controller open, but really isn't protected by it.
Fixes: cd6484e1830b ("serdev: Introduce new bus for serial attached devices")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serdev/serdev-ttyport.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -149,8 +149,10 @@ static void ttyport_close(struct serdev_
clear_bit(SERPORT_ACTIVE, &serport->flags);
+ tty_lock(tty);
if (tty->ops->close)
tty->ops->close(tty, NULL);
+ tty_unlock(tty);
tty_release_struct(tty, serport->tty_idx);
}