On Tue, Aug 12, 2025 at 02:46:24PM +0200, Jiri Kosina wrote:

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?
 

From 75e52defd4b2fd138285c5ad953942e2e6cf2fbb Mon Sep 17 00:00:00 2001
From: Minjong Kim <redacted>
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 <redacted>
---
 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)
+		return;
+
 	if (!data)
 		goto err_free;

--

2.34.1

I move it below the declarations.

Best regards,