[PATCH v2] HID: hid-ntrig: Prevent memory leak in ntrig_report_version()

[PATCH v2] HID: hid-ntrig: Prevent memory leak in ntrig_report_version()

[Masami Ichikawa]

Use a scope-based cleanup helper for the buffer allocated with kmalloc()
in ntrig_report_version() to simplify the cleanup logic and prevent
memory leaks.

Fixes: 185c926283da ("HID: hid-ntrig: fix unable to handle page fault in ntrig_report_version()")
Signed-off-by: Masami Ichikawa <masami256@gmail.com>
---
Changes from v1:
- Rewrite patch title
- Use scope-based cleanup to drop goto-based error path
---
 drivers/hid/hid-ntrig.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
index 0f76e241e0af..a7f10c45f62b 100644
--- a/drivers/hid/hid-ntrig.c
+++ b/drivers/hid/hid-ntrig.c
@@ -142,13 +142,13 @@ static void ntrig_report_version(struct hid_device *hdev)
 	int ret;
 	char buf[20];
 	struct usb_device *usb_dev = hid_to_usb_dev(hdev);
-	unsigned char *data = kmalloc(8, GFP_KERNEL);
+	unsigned char *data __free(kfree) = kmalloc(8, GFP_KERNEL);
 
 	if (!hid_is_usb(hdev))
 		return;
 
 	if (!data)
-		goto err_free;
+		return;
 
 	ret = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
 			      USB_REQ_CLEAR_FEATURE,
@@ -163,9 +163,6 @@ static void ntrig_report_version(struct hid_device *hdev)
 		hid_info(hdev, "Firmware version: %s (%02x%02x %02x%02x)\n",
 			 buf, data[2], data[3], data[4], data[5]);
 	}
-
-err_free:
-	kfree(data);
 }
 
 static ssize_t show_phys_width(struct device *dev,
-- 
2.51.0

Re: [PATCH v2] HID: hid-ntrig: Prevent memory leak in ntrig_report_version()

[Jiri Kosina]

On Sun, 21 Sep 2025, Masami Ichikawa wrote:

> Use a scope-based cleanup helper for the buffer allocated with kmalloc()
> in ntrig_report_version() to simplify the cleanup logic and prevent
> memory leaks.
> 
> Fixes: 185c926283da ("HID: hid-ntrig: fix unable to handle page fault in ntrig_report_version()")
> Signed-off-by: Masami Ichikawa <masami256@gmail.com>

I have added an explicit reference to the real actual leak being fixed 
into the changelog, and applied, thanks.

-- 
Jiri Kosina
SUSE Labs