lkml.org 
[lkml]   [2014]   [Dec]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] usb: gadget: udc-core: call udc_stop() before gadget unbind
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@samsung.com>
> ---
> 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



\
 
 \ /
  Last update: 2014-12-15 17:41    [W:0.118 / U:1.308 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site