On Fri, 12 Dec 2014, Robert Baldyga wrote: > As usb function drivers assumes that all usb request will be completed > before function unbind call, we should supply such behavior. In some > cases ep_disable() won't kill all request effectively, because some > IN requests can be in running state. In such situation it's possible > to have unbind function called before last request completion, which > can cause problems. > > For example unbinding f_ecm function while request on 'notify' endpoint > is not completed, ends up NULL pointer dereference in unbind() function. > > usb_gadget_udc_stop() call causes completion of all requests so if it's > called before gadget unbind there is no risk that some of requests will > stay uncompleted. > > Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx> > --- > drivers/usb/gadget/udc/udc-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c > index e31d574..6f0d233 100644 > --- a/drivers/usb/gadget/udc/udc-core.c > +++ b/drivers/usb/gadget/udc/udc-core.c > @@ -331,8 +331,8 @@ static void usb_gadget_remove_driver(struct usb_udc *udc) > > usb_gadget_disconnect(udc->gadget); > udc->driver->disconnect(udc->gadget); > - udc->driver->unbind(udc->gadget); > usb_gadget_udc_stop(udc); > + udc->driver->unbind(udc->gadget); > > udc->driver = NULL; > udc->dev.driver = NULL; There has been a lot of churn and a lot of bug fixes involving those lines of code. Have you checked the git log for this function? It's quite possible that interchanging those two statements will recreate a bug that has already been fixed. Alan Stern -- 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
