USB: sierra: add more checks on shutdown

This should help with any potential NULL pointer usages as reported by a
few users.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 4865aff892e8..644607de4c11 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -577,7 +577,12 @@ static void sierra_shutdown(struct usb_serial *serial)
         /* Stop reading/writing urbs */
         for (i = 0; i < serial->num_ports; ++i) {
                 port = serial->port[i];
+                if (!port)
+                        continue;
                 portdata = usb_get_serial_port_data(port);
+                if (!portdata)
+                        continue;
+
                 for (j = 0; j < N_IN_URB; j++)
                         usb_unlink_urb(portdata->in_urbs[j]);
                 for (j = 0; j < N_OUT_URB; j++)
@@ -587,7 +592,11 @@ static void sierra_shutdown(struct usb_serial *serial)
         /* Now free them */
         for (i = 0; i < serial->num_ports; ++i) {
                 port = serial->port[i];
+                if (!port)
+                        continue;
                 portdata = usb_get_serial_port_data(port);
+                if (!portdata)
+                        continue;
 
                 for (j = 0; j < N_IN_URB; j++) {
                         if (portdata->in_urbs[j]) {
@@ -606,6 +615,8 @@ static void sierra_shutdown(struct usb_serial *serial)
         /* Now free per port private data */
         for (i = 0; i < serial->num_ports; i++) {
                 port = serial->port[i];
+                if (!port)
+                        continue;
                 kfree(usb_get_serial_port_data(port));
         }
 }