hso: fix oops in read/write callbacks

The tty may be closed already when the read/write callbacks are called.
This patch checks that the ttys still exist before waking them up.

Signed-off-by: Olivier Blin <blino@mandriva.com>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Jari Tenhunen <jari.tenhunen@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 031d07b105af..94a27f764e6b 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1467,7 +1467,8 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
                 return;
         }
         hso_put_activity(serial->parent);
-        tty_wakeup(serial->tty);
+        if (serial->tty)
+                tty_wakeup(serial->tty);
         hso_kick_transmit(serial);
 
         D1(" ");
@@ -1538,7 +1539,8 @@ static void ctrl_callback(struct urb *urb)
                         clear_bit(HSO_SERIAL_FLAG_RX_SENT, &serial->flags);
         } else {
                 hso_put_activity(serial->parent);
-                tty_wakeup(serial->tty);
+                if (serial->tty)
+                        tty_wakeup(serial->tty);
                 /* response to a write command */
                 hso_kick_transmit(serial);
         }