Re: rtl8xxxu 4.4.5(from f23): I get a panic adding a new device to the driver

[poma <pomidorabelisima@gmail.com>]

On 17.03.2016 19:02, Jes Sorensen wrote:
> Jes Sorensen <Jes.Sorensen@redhat.com> writes:
>> Xose Vazquez Perez <xose.vazquez@gmail.com> writes:
>>> Hi,
>>>
>>> If I do:
>>> # echo "0bda 8176" > /sys/bus/usb/drivers/rtl8xxxu/new_id
>>
>> Hi Xose,
>>
>> Yes please don't do that. The rtl8xxxu driver relies on the .driver_info
>> field in struct use_device_id to carry information for the different
>> types of devices. If you hot add a device like above, the driver will
>> fail because that field now contains a NULL pointer.
>>
>> I should probably add a check for it in the probe function, but it will
>> simply be there to spit out a warning that it doesn't work to hot add a
>> device like this.
>>
>> If you build it with CONFIG_RTL8XXXU_UNTESTED the 0bda:8176 should be
>> included in the device list.
>>
>> Cheers,
>> Jes
> 
> Hi Xose,
> 
> I added the following patch to my tree to avoid this.
> 
> Cheers,
> Jes
> 
> commit 9202f4947aac1d60084ee79c9b5294eb42ba59dc
> Author: Jes Sorensen <Jes.Sorensen@redhat.com>
> Date:   Thu Mar 17 13:53:48 2016 -0400
> 
>     rtl8xxxu: Fix OOPS if user tries to add device via /sys
>     
>     This driver relies on driver_info in struct usb_device_id, hence
>     adding a device via  /sys/bus/usb/drivers/rtl8xxxu/new_id would result
>     in a NULL pointer dereference.
>     
>     Instead print a message and return -ENODEV
>     
>     Reported-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
>     Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> 
> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c
> index 8d893f4..55fc00e 100644
> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c
> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c
> @@ -9671,6 +9671,15 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
>  
>  	udev = usb_get_dev(interface_to_usbdev(interface));
>  
> +	if (!id->driver_info) {
> +		dev_warn(&udev->dev,
> +			 "rtl8xxxu relies on driver_info in struct usb_device_id.\n");
> +		dev_warn(&udev->dev,
> +			 "Adding a device via /sys/bus/usb/drivers/rtl8xxxu/new_id is not supported!\n");
> +		ret = -ENODEV;
> +		goto exit;
> +	}
> +
>  	switch (id->idVendor) {
>  	case USB_VENDOR_ID_REALTEK:
>  		switch(id->idProduct) {
>


Dynamic adding and removing a new device IDs to a USB device drivers
via /sys/bus/usb/drivers/.../[new_id|remove_id]
https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-usb

is not supported only with rtl8xxxu?