On Tue, Jan 29, 2019 at 09:39:28PM -0800, Myungho Jung wrote: > tiocmget() and tiocmset() operations are optional and some tty drivers > like pty miss the operations. We need NULL check to prevent from > dereference. > > Signed-off-by: Myungho Jung <mhjungk@xxxxxxxxx> > --- > drivers/bluetooth/hci_ath.c | 6 ++++++ > drivers/bluetooth/hci_ldisc.c | 4 ++++ > 2 files changed, 10 insertions(+) Ah, you had already submitted a v2. I still suggest splitting this one in two patches and that you add a Fixes and stable tag to each so that they both get backported to stable. Also, when resubmitting, make sure to include a short changelog here below the cut-off line (---). > > diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c > index d568fbd94d6c..fb9f6323a911 100644 > --- a/drivers/bluetooth/hci_ath.c > +++ b/drivers/bluetooth/hci_ath.c > @@ -185,8 +185,14 @@ static int ath_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr) > > static int ath_setup(struct hci_uart *hu) > { > + struct tty_struct *tty = hu->tty; > + > BT_DBG("hu %p", hu); > > + /* tty driver should support operations to set RTS */ > + if (!tty->driver->ops->tiocmget || !tty->driver->ops->tiocmset) > + return -EOPNOTSUPP; -ENODEV might be more appropriate. Johan