Re: [PATCH] HID: hid-ntrig: fix unable to handle page fault in ntrig_report_version()

[Jiri Kosina]

On Thu, 17 Jul 2025, Minjong Kim wrote:

> in ntrig_report_version(), hdev parameter passed from hid_probe().
> sending descriptor to /dev/uhid can make hdev->dev.parent->parent to null
> if hdev->dev.parent->parent is null, usb_dev has
> invalid address(0xffffffffffffff58) that hid_to_usb_dev(hdev) returned
> when usb_rcvctrlpipe() use usb_dev,it trigger
> page fault error for address(0xffffffffffffff58)
> 
> add null check logic to ntrig_report_version()
> before calling hid_to_usb_dev()
> 
> Signed-off-by: Minjong Kim <minbell.kim@xxxxxxxxxxx>
> ---
>  drivers/hid/hid-ntrig.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
> index 2738ce947434f904f32e9a1979b1681c66972ff9..96d3300655b5aa1621015b8e1fb511e6f616a713 100644
> --- a/drivers/hid/hid-ntrig.c
> +++ b/drivers/hid/hid-ntrig.c
> @@ -139,6 +139,10 @@ static inline void ntrig_set_mode(struct hid_device *hdev, const int mode)
>  
>  static void ntrig_report_version(struct hid_device *hdev)
>  {
> +
> +	if (!hdev->dev.parent->parent)
> +		return;
> +
>  	int ret;
>  	char buf[20];
>  	struct usb_device *usb_dev = hid_to_usb_dev(hdev);

I know that mixing declarations and code is fine these days, but we 
haven't been progressive enough to switch to that coding style in HID 
subsystem yet :) Would you be willing to move it below the declarations?

Thanks,

-- 
Jiri Kosina
SUSE Labs