Hi,
Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes:
> On Mon, 3 Apr 2017, Roger Quadros wrote:
>
>> allow usb_del_gadget_udc() and usb add_gadget_udc() to be called
>> repeatedly on the same gadget->dev structure.
>>
>> We need to clear the gadget->dev structure so that kobject_init()
>> doesn't complain about already initialized object.
>>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>> drivers/usb/gadget/udc/core.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
>> index d685d82..efce68e 100644
>> --- a/drivers/usb/gadget/udc/core.c
>> +++ b/drivers/usb/gadget/udc/core.c
>> @@ -1273,6 +1273,7 @@ void usb_del_gadget_udc(struct usb_gadget *gadget)
>> flush_work(&gadget->work);
>> device_unregister(&udc->dev);
>> device_unregister(&gadget->dev);
>> + memset(&gadget->dev, 0x00, sizeof(gadget->dev));
>> }
>> EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
>
> Isn't this dangerous? It's quite possible that the device_unregister()
not on the gadget API, no.
> call on the previous line invokes the gadget->dev.release callback,
> which might deallocate gadget. If that happens, your new memset will
> oops.
that won't happen. struct usb_gadget is a member of the UDC's private
structure, like this:
struct dwc3 {
[...]
struct usb_gadget gadget;
struct usb_gadget_driver *gadget_driver;
[...]
};
I'm actually thinking that struct usb_gadget shouldn't have a struct
device at all. Just a pointer to a device, that would solve all these
issues.
--
balbi
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