release/5.2.37/USB-serial-ch341-handle-unbound-port-at-reset_resume.patch

From 65d88b566dc84278cda11d22a6ea29ca5dd84ee1 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Fri, 17 Jan 2020 10:50:22 +0100
Subject: [PATCH] USB: serial: ch341: handle unbound port at reset_resume

commit 4d5ef53f75c22d28f490bcc5c771fcc610a9afa4 upstream.

Check for NULL port data in reset_resume() to avoid dereferencing a NULL
pointer in case the port device isn't bound to a driver (e.g. after a
failed control request at port probe).

Fixes: 1ded7ea47b88 ("USB: ch341 serial: fix port number changed after resume")
Cc: stable <stable@vger.kernel.org>     # 2.6.30
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 3bb1fff02bed..955ab97b9b22 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -589,9 +589,13 @@ static int ch341_tiocmget(struct tty_struct *tty)
 static int ch341_reset_resume(struct usb_serial *serial)
 {
 	struct usb_serial_port *port = serial->port[0];
-	struct ch341_private *priv = usb_get_serial_port_data(port);
+	struct ch341_private *priv;
 	int ret;
 
+	priv = usb_get_serial_port_data(port);
+	if (!priv)
+		return 0;
+
 	/* reconfigure ch341 serial port after bus-reset */
 	ch341_configure(serial->dev, priv);
 
-- 
2.7.4