From b2ca699076573c94fee9a73cb0d8645383b602a0 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 13 Feb 2013 17:53:28 +0100 Subject: 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 Cc: stable Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/sierra.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'drivers/usb/serial/sierra.c') diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c index af06f2f5f38b..d4426c038c32 100644 --- a/drivers/usb/serial/sierra.c +++ b/drivers/usb/serial/sierra.c @@ -861,19 +861,13 @@ static int sierra_open(struct tty_struct *tty, struct usb_serial_port *port) static void sierra_dtr_rts(struct usb_serial_port *port, int on) { - struct usb_serial *serial = port->serial; struct sierra_port_private *portdata; portdata = usb_get_serial_port_data(port); portdata->rts_state = on; portdata->dtr_state = on; - if (serial->dev) { - mutex_lock(&serial->disc_mutex); - if (!serial->disconnected) - sierra_send_setup(port); - mutex_unlock(&serial->disc_mutex); - } + sierra_send_setup(port); } static int sierra_startup(struct usb_serial *serial) -- cgit v1.2.3