Inconsistency in usb_add_gadget_udc_release() interface

[Alexey Khoroshilov]

Hello,

usb_add_gadget_udc_release() gets release() argument that allows to
release user resources.

As far as I can see, the release() is called on error paths 
of usb_add_gadget_udc_release() as a result of
put_device(&gadget->dev);
except for the only path going via err1.

As a result a caller of the usb_add_gadget_udc_release() have no chance
to know if the release() was invoked or not.

It may lead to memory leaks (drivers/usb/gadget/udc/snps_udc_core.c)
or to double free (drivers/usb/gadget/udc/fsl_udc_core.c).

Is my reading correct? If so, should we always call release() on error paths?

--
Alexey Khoroshilov
Linux Verification Center, ISPRAS
web: http://linuxtesting.org