4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stefan Agner <stefan@xxxxxxxx>
commit 3216c622a24b0ebb9c159a8d1daf7f17a106b3f5 upstream.
The function tty_port_tty_get() gets a reference to the tty. Since
the code is not using tty_port_tty_set(), the reference is kept
even after closing the tty.
Avoid using tty_port_tty_get() by directly access the tty instance.
Since lpuart_start_rx_dma() is called from the .startup() and
.set_termios() callback, it is safe to assume the tty instance is
valid.
Cc: stable@xxxxxxxxxxxxxxx # v4.9+
Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx")
Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/fsl_lpuart.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -833,7 +833,8 @@ static inline int lpuart_start_rx_dma(st
struct circ_buf *ring = &sport->rx_ring;
int ret, nent;
int bits, baud;
- struct tty_struct *tty = tty_port_tty_get(&sport->port.state->port);
+ struct tty_port *port = &sport->port.state->port;
+ struct tty_struct *tty = port->tty;
struct ktermios *termios = &tty->termios;
baud = tty_get_baud_rate(tty);
