u_serial.c - Force destroy tty_port in gserial_free_port

Issuing a modprobe -r g_serial command to the target over the gadget serial communications line causes modprobe to enter uninterruptable sleep, leaving the system in an unstable state.

The associated tty_port.count won't drop to 0 because the command is issued over the very line being removed.

Destroying the tty_port will ensure that resources are freed and modprobe will not hang.

Signed-off-by Andre Wolokita <[email protected]>

---
 drivers/usb/gadget/function/u_serial.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/usb/gadget/function/u_serial.c +1 -1

index ad0aca8..db631c4 100644
@@ -1074,10 +1074,10 @@ static int gs_closed(struct gs_port *port)
 static void gserial_free_port(struct gs_port *port)
 {
        tasklet_kill(&port->push);
+       tty_port_destroy(&port->port);
        /* wait for old opens to finish */
        wait_event(port->port.close_wait, gs_closed(port));
        WARN_ON(port->port_usb != NULL);
-       tty_port_destroy(&port->port);
        kfree(port);
 }