Hello linux community expert:
>> diff --git a/drivers/usb/gadget/function/u_serial.c
>> b/drivers/usb/gadget/function/u_serial.c
>> index b394105e55d6..65637d53bf02
>> --- a/drivers/usb/gadget/function/u_serial.c
>> +++ b/drivers/usb/gadget/function/u_serial.c
>> @@ -454,6 +454,14 @@ static void gs_read_complete(struct usb_ep *ep,
>> struct usb_request *req) {
>> struct gs_port *port = ep->driver_data;
>>
>> + /* When port is NULL, return to avoid panic. */
>> + if (!port)
>> + return;
>> +
>This doesn't protect the port from going to NULL right after the above the check. Since you mentioned gser_disconnect is making port to NULL, add the serial_port_lock to protect port (just like its done on gser_disconnect/suspend/resume). Something like this would do.
OK, it is more reasonable to modify it as follows, I will modify it again.
>diff --git a/drivers/usb/gadget/function/u_serial.c
>b/drivers/usb/gadget/function/u_serial.c
>index f975dc03a190..a33f8cd871ac 100644
>--- a/drivers/usb/gadget/function/u_serial.c
>+++ b/drivers/usb/gadget/function/u_serial.c
>@@ -451,10 +451,21 @@ static void gs_rx_push(struct work_struct *work)
>static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) {
>- struct gs_port *port = ep->driver_data;
>+ struct gs_port *port;
>+ unsigned long flags;
>+
>+ spin_lock_irqsave(&serial_port_lock, flags);
>+ port = ep->driver_data;
>+
>+ if (!port) {
>+ spin_unlock_irqrestore(&serial_port_lock, flags);
>+ return;
>+ }
>- /* Queue all received data until the tty layer is ready for it. */
> spin_lock(&port->port_lock);
>+ spin_unlock(&serial_port_lock);
>+
>+ /* Queue all received data until the tty layer is ready for it.
>+ */
> list_add_tail(&req->list, &port->read_queue);
> schedule_delayed_work(&port->push, 0);
> spin_unlock(&port->port_lock);
>
>> /* Queue all received data until the tty layer is ready for it. */
>> spin_lock(&port->port_lock);
>> list_add_tail(&req->list, &port->read_queue); @@ -465,6 +473,14 @@
>> static void gs_write_complete(struct usb_ep *ep, struct usb_request
>> *req) {
>> struct gs_port *port = ep->driver_data;
>>
>> + /* When port is NULL, return to avoid panic. */
>> + if (!port)
>> + return;
>> +
>> spin_lock(&port->port_lock);
>> list_add(&req->list, &port->write_pool);
>> port->write_started--;
>Same here also
Thanks
