diff options
| author | Johan Hovold <jhovold@gmail.com> | 2013-02-13 17:53:28 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-13 09:20:06 -0800 |
| commit | b2ca699076573c94fee9a73cb0d8645383b602a0 (patch) | |
| tree | b9579ce8ed1511a5b3a234b03392b3c095de9231 /drivers/usb/serial/usb-serial.c | |
| parent | cd565279e51bedee1b2988e84f9b3bef485adeb6 (diff) | |
USB: serial: fix null-pointer dereferences on disconnect
Make sure serial-driver dtr_rts is called with disc_mutex held after
checking the disconnected flag.
Due to a bug in the tty layer, dtr_rts may get called after a device has
been disconnected and the tty-device unregistered. Some drivers have had
individual checks for disconnect to make sure the disconnected interface
was not accessed, but this should really be handled in usb-serial core
(at least until the long-standing tty-bug has been fixed).
Note that the problem has been made more acute with commit 0998d0631001
("device-core: Ensure drvdata = NULL when no driver is bound") as the
port data is now also NULL when dtr_rts is called resulting in further
oopses.
Reported-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/serial/usb-serial.c')
| -rw-r--r-- | drivers/usb/serial/usb-serial.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 0a17f5942552..a19ed74d770d 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -694,10 +694,20 @@ static int serial_carrier_raised(struct tty_port *port) static void serial_dtr_rts(struct tty_port *port, int on) { struct usb_serial_port *p = container_of(port, struct usb_serial_port, port); - struct usb_serial_driver *drv = p->serial->type; + struct usb_serial *serial = p->serial; + struct usb_serial_driver *drv = serial->type; - if (drv->dtr_rts) + if (!drv->dtr_rts) + return; + /* + * Work-around bug in the tty-layer which can result in dtr_rts + * being called after a disconnect (and tty_unregister_device + * has returned). Remove once bug has been squashed. + */ + mutex_lock(&serial->disc_mutex); + if (!serial->disconnected) drv->dtr_rts(p, on); + mutex_unlock(&serial->disc_mutex); } static const struct tty_port_operations serial_port_ops = { |