On Tuesday 16 October 2012 at 10:40:26, Lars-Peter Clausen wrote: > On 10/12/2012 04:34 PM, Lars Poeschel wrote: > > [...] > > +static void vprbrd_dev_release(struct device *dev) > > +{ > > + return; > > A empty release callback is usually a good indicator that something is > wrong. The release callback will be called once the last reference to the > device has been called, so the memory associated with the device should not > be freed before the release callback has been called, otherwise the memory > might be accessed after it has been freed... > > > +} > > + > > +static void vprbrd_free(struct vprbrd *dev) > > +{ > > + usb_put_dev(dev->usb_dev); > > + kfree(dev); > > ..., so this kfree should be moved from here to the release callback.
Thank you for catching that one! > Btw. I'm wondering why is the extra platform device required? Can't you not > just use the usb device as the parent device for the mfd cells? This is what I first did, but this does not work. You can read about my first thoughts why this is not working here: (To sum it up: The device is housed in an usb_device, not a platform_device and This usb_device has no mfd_cell member.) https://lkml.org/lkml/2012/9/28/327 As I got a bit more deeper I also noticed, that mfd_add_devices (obviously) adds the devices "as childs" to the parent device. mfd_remove_devices then removes ALL "child" devices from the parent, not only those added by mfd_add_devices before. This does not work in the case of the usb parent device, because it has other childs that the usb layer added before (some endpoints and stuff). So I had to construct an "empty" (in sense of childs) mock platform_device between the usb and mfd. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/