patch "USB: serial: quatech2: handle unbound ports" added to usb-linus

This is a note to let you know that I've just added the patch titled

USB: serial: quatech2: handle unbound ports

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 9715a43eea77e42678a1002623f2d9a78f5b81a1 Mon Sep 17 00:00:00 2001
From: Johan Hovold <[email protected]>
Date: Fri, 17 Jan 2020 15:35:26 +0100
Subject: USB: serial: quatech2: handle unbound ports

Check for NULL port data in the modem- and line-status handlers to avoid dereferencing a NULL pointer in the unlikely case where a port device isn't bound to a driver (e.g. after an allocation failure on port probe).

Note that the other (stubbed) event handlers qt2_process_xmit_empty() and qt2_process_flush() would need similar sanity checks in case they are ever implemented.

---
 drivers/usb/serial/quatech2.c | 6 ++++++
 1 file changed, 6 insertions(+)

index a62981ca7a73..f93b81a297d6 100644
@@ -841,7 +841,10 @@ static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch)
 	u8 newMSR = (u8) *ch;
 	unsigned long flags;
 
+	/* May be called from qt2_process_read_urb() for an unbound port. */
 	port_priv = usb_get_serial_port_data(port);
+	if (!port_priv)
+		return;
 
 	spin_lock_irqsave(&port_priv->lock, flags);
 	port_priv->shadowMSR = newMSR;

@@ -869,7 +872,10 @@ static void qt2_update_lsr(struct usb_serial_port *port, unsigned char *ch)
 	unsigned long flags;
 	u8 newLSR = (u8) *ch;
 
+	/* May be called from qt2_process_read_urb() for an unbound port. */
 	port_priv = usb_get_serial_port_data(port);
+	if (!port_priv)
+		return;
 
 	if (newLSR & UART_LSR_BI)
 		newLSR &= (u8) (UART_LSR_OE | UART_LSR_BI);

2.25.0