Messages in this thread Patch in this message | | | From | Johan Hovold <> | Subject | [PATCH 4/8] serdev: ttyport: fix NULL-deref on hangup | Date | Fri, 3 Nov 2017 15:30:55 +0100 |
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Make sure to use a properly refcounted tty_struct in write_wake up to avoid dereferencing a NULL-pointer when a port is being hung up.
Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver") Cc: stable <stable@vger.kernel.org> # 4.11 Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/tty/serdev/serdev-ttyport.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c index b8bc60a251c6..31c05665a0e6 100644 --- a/drivers/tty/serdev/serdev-ttyport.c +++ b/drivers/tty/serdev/serdev-ttyport.c @@ -57,12 +57,19 @@ static void ttyport_write_wakeup(struct tty_port *port) { struct serdev_controller *ctrl = port->client_data; struct serport *serport = serdev_controller_get_drvdata(ctrl); + struct tty_struct *tty; + + tty = tty_port_tty_get(port); + if (!tty) + return; - if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags) && + if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) && test_bit(SERPORT_ACTIVE, &serport->flags)) serdev_controller_write_wakeup(ctrl); - wake_up_interruptible_poll(&port->tty->write_wait, POLLOUT); + wake_up_interruptible_poll(&tty->write_wait, POLLOUT); + + tty_kref_put(tty); } static const struct tty_port_client_operations client_ops = { -- 2.15.0
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