[PATCH 19/24] serial: imx: fix the tty reference of the wakeup event

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Josef Bacik <josef@toxicpanda.com>

To report a wakeup event, imx_uart_enable_wakeup() gets the tty with
tty_port_tty_get() and never puts it: each wakeup by the UART leaks a
reference, and the tty is not freed when it is closed.

Fixes: 0cfadf4bcd28 ("tty: serial: imx: Add missing wakeup event reporting")
Cc: stable <stable@kernel.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Frank Li <Frank.Li@nxp.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Robin Gong <yibin.gong@nxp.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Pan Chuang <panchuang@vivo.com>
Cc: Karl Mehltretter <kmehltretter@gmail.com>
Cc: Sherry Sun <sherry.sun@nxp.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/imx.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 986fefb45c63..18892fc4a35b 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2742,8 +2742,14 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
 		imx_uart_writel(sport, ucr1, UCR1);
 	}
 
-	if (wake_active && irqd_is_wakeup_set(irq_get_irq_data(sport->port.irq)))
-		pm_wakeup_event(tty_port_tty_get(port)->dev, 0);
+	if (wake_active && irqd_is_wakeup_set(irq_get_irq_data(sport->port.irq))) {
+		struct tty_struct *tty = tty_port_tty_get(port);
+
+		if (tty) {
+			pm_wakeup_event(tty->dev, 0);
+			tty_kref_put(tty);
+		}
+	}
 
 	uart_port_unlock_irq(&sport->port);
 }

-- 
2.56.0