USB: serial: sierra driver indat_callback fix
A crash has been reported with sierra driver on disconnect with
Ubuntu/Lucid distribution based on kernel-2.6.32.
The cause of the crash was determined as "NULL tty pointer was being
referenced" and the NULL pointer was passed by sierra_indat_callback().
This patch modifies sierra_indat_callback() function to check for NULL
tty structure pointer. This modification prevents a crash from happening
when the device is disconnected.
This patch fixes the bug reported in Launchpad:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/511157
Signed-off-by: Elina Pasheva <epasheva@sierrawireless.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 6aeea400..fcec466 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -594,14 +594,17 @@
} else {
if (urb->actual_length) {
tty = tty_port_tty_get(&port->port);
+ if (tty) {
+ tty_buffer_request_room(tty,
+ urb->actual_length);
+ tty_insert_flip_string(tty, data,
+ urb->actual_length);
+ tty_flip_buffer_push(tty);
- tty_buffer_request_room(tty, urb->actual_length);
- tty_insert_flip_string(tty, data, urb->actual_length);
- tty_flip_buffer_push(tty);
-
- tty_kref_put(tty);
- usb_serial_debug_data(debug, &port->dev, __func__,
- urb->actual_length, data);
+ tty_kref_put(tty);
+ usb_serial_debug_data(debug, &port->dev,
+ __func__, urb->actual_length, data);
+ }
} else {
dev_dbg(&port->dev, "%s: empty read urb"
" received\n", __func__);