Re: [PATCH v3] HID: hid-ntrig: fix unable to handle page fault in ntrig_report_version()

[Minjong Kim]

 On Wed, Aug 13, 2025 at 10:39:37AM +0200, Benjamin Tissoires wrote:
> On Aug 13 2025, Minjong Kim wrote:
> > 
> > From 75e52defd4b2fd138285c5ad953942e2e6cf2fbb Mon Sep 17 00:00:00 2001
> > From: Minjong Kim <minbell.kim@xxxxxxxxxxx>
> > Date: Thu, 17 Jul 2025 14:37:47 +0900
> > Subject: [PATCH v2] HID: hid-ntrig: fix unable to handle page fault in
> >  ntrig_report_version()
> > 
> > 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 | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
> > index 2738ce947434..fa948d9e236c 100644
> > --- a/drivers/hid/hid-ntrig.c
> > +++ b/drivers/hid/hid-ntrig.c
> > @@ -144,6 +144,9 @@ static void ntrig_report_version(struct hid_device *hdev)
> >  	struct usb_device *usb_dev = hid_to_usb_dev(hdev);
> >  	unsigned char *data = kmalloc(8, GFP_KERNEL);
> > 
> > +	if (!hdev->dev.parent->parent)
> 
> Why simply not use if(!hid_is_usb(hdev)) instead?
> 
> Cheers,
> Benjamin
>