When usb gadget is set gadget serial function, it will be crash in below situation. It will clean the 'port->port_usb' pointer in gserial_disconnect() function when usb link is inactive, but it will release lock for disabling the endpoints in this function. Druing the lock release period, it maybe complete one request to issue gs_write_complete()--->gs_start_tx() function, but the 'port->port_usb' pointer had been set NULL, thus it will be crash in gs_start_tx() function. This patch adds the 'port->port_usb' pointer checking in gs_start_tx() function to avoid this situation. Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx> --- drivers/usb/gadget/function/u_serial.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index 3580f19..66a0910 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -375,10 +375,15 @@ __acquires(&port->port_lock) */ { struct list_head *pool = &port->write_pool; - struct usb_ep *in = port->port_usb->in; + struct usb_ep *in; int status = 0; bool do_tty_wake = false; + if (!port->port_usb) + return status; + + in = port->port_usb->in; + while (!port->write_busy && !list_empty(pool)) { struct usb_request *req; int len; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html