From: Johan Hovold johan@kernel.org
commit 6f1d1dc8d540a9aa6e39b9cb86d3a67bbc1c8d8d upstream.
Fix races between closing a port and opening or closing another port on the same device which could lead to a failure to start or stop the shared interrupt URB. The latter could potentially cause a use-after-free or worse in the completion handler on driver unbind.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable stable@vger.kernel.org Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/serial/ti_usb_3410_5052.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)
--- a/drivers/usb/serial/ti_usb_3410_5052.c +++ b/drivers/usb/serial/ti_usb_3410_5052.c @@ -780,7 +780,6 @@ static void ti_close(struct usb_serial_p struct ti_port *tport; int port_number; int status; - int do_unlock; unsigned long flags;
tdev = usb_get_serial_data(port->serial); @@ -804,16 +803,13 @@ static void ti_close(struct usb_serial_p "%s - cannot send close port command, %d\n" , __func__, status);
- /* if mutex_lock is interrupted, continue anyway */ - do_unlock = !mutex_lock_interruptible(&tdev->td_open_close_lock); + mutex_lock(&tdev->td_open_close_lock); --tport->tp_tdev->td_open_port_count; - if (tport->tp_tdev->td_open_port_count <= 0) { + if (tport->tp_tdev->td_open_port_count == 0) { /* last port is closed, shut down interrupt urb */ usb_kill_urb(port->serial->port[0]->interrupt_in_urb); - tport->tp_tdev->td_open_port_count = 0; } - if (do_unlock) - mutex_unlock(&tdev->td_open_close_lock); + mutex_unlock(&tdev->td_open_close_lock); }