Re: [PATCH] usb: gadget: goku_udc: fix kobject warning on probe failure

[Greg Kroah-Hartman]

On Wed, Aug 26, 2026 at 11:35:58AM +0800, Cheng Lingfei wrote:
> goku_probe() calls goku_remove() when hardware initialization fails, but
> the gadget device is initialized only near the end of probe. As a result,
> goku_remove() calls usb_del_gadget_udc(), which drops a reference to an
> uninitialized gadget device and triggers a kobject warning.
> 
> Initialize the gadget device immediately after allocating the controller,
> but add it only after all hardware resources have been acquired. Track the
> gadget and proc entry registration state so goku_remove() can safely clean
> up both partial probe state and a fully initialized device.
> 
> Use the split gadget removal API and drop the final gadget reference only
> after all hardware resources have been released.
> 
> Also obtain the controller from the embedded gadget device in the release
> callback. Driver data is set on the PCI device rather than the gadget
> device, so using dev_get_drvdata() there fails to free the controller.
> 
> Use a per-device name for the debug proc entry so that multiple
> controllers can be registered without colliding on /proc/driver/udc.
> 
> Fixes: 3301c215a2bb ("USB: UDC: Expand device model API interface")
> Reported-by: syzbot+06ec7624018233e17113@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=06ec7624018233e17113
> Tested-by: syzbot+06ec7624018233e17113@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> Signed-off-by: Cheng Lingfei <chenglingfei@xxxxxxxxxxx>

No Assisted-by: line?

And do you see this happening in a real device and not just a fake one?

And why is this driver using proc at all, shouldn't that be in debugfs
instead?

thanks,

greg k-h