RE: [PATCH] usb: gadget: udc-core: call udc_stop() before gadget unbind

Krzysztof Opasiak
2014-12-12T13:51:49Z

> -----Original Message-----
> From: Robert Baldyga [mailto:r.baldyga@samsung.com]
> Sent: Friday, December 12, 2014 2:17 PM
> To: balbi@ti.com
> Cc: gregkh@linuxfoundation.org; peter.chen@freescale.com; linux-
> usb@vger.kernel.org; linux-kernel@vger.kernel.org;
> m.szyprowski@samsung.com; k.opasiak@samsung.com; Robert Baldyga
> Subject: [PATCH] usb: gadget: udc-core: call udc_stop() before
> gadget unbind
>
> 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>

This finally solves issue described before in [1]

Tested-by: Krzysztof Opasiak <k.opasiak@samsung.com>

Footnotes:
1 - https://lkml.org/lkml/2014/12/9/283

--
Krzysztof Opasiak
Samsung R&D Institute Poland
Samsung Electronics
k.opasiak@samsung.com