[PATCH 1/2] HID: alps: unregister DualPoint Stick input device on remove

[Chen Changcheng <chenchangcheng@kylinos.cn>]

alps_input_configured() allocates a second input device ("DualPoint
Stick") with input_allocate_device() and registers it, but the
alps_driver struct has no .remove handler and input2 is not tracked in
hdev->inputs.  The default remove path (hid_hw_stop -> hidinput_disconnect)
only iterates hdev->inputs, so input2 is never unregistered and leaks
on every device removal.

Add a .remove handler that stops the device first (preventing URB
callbacks from touching input2 during teardown) and then unregisters
input2.

Fixes: 2562756dde55 ("HID: add Alps I2C HID Touchpad-Stick support")
Cc: stable@vger.kernel.org
Signed-off-by: Chen Changcheng <chenchangcheng@kylinos.cn>
---
 drivers/hid/hid-alps.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/hid/hid-alps.c b/drivers/hid/hid-alps.c
index 67179e3fe39b..370635f5b704 100644
--- a/drivers/hid/hid-alps.c
+++ b/drivers/hid/hid-alps.c
@@ -823,6 +823,24 @@ static int alps_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	return 0;
 }
 
+static void alps_remove(struct hid_device *hdev)
+{
+	struct alps_dev *data = hid_get_drvdata(hdev);
+
+	/*
+	 * input2 ("DualPoint Stick") is allocated separately and is not
+	 * tracked in hdev->inputs, so the default remove path
+	 * (hid_hw_stop -> hidinput_disconnect) does not unregister it.
+	 *
+	 * Stop the device first so that no URB callback can touch input2
+	 * while it is being unregistered, then drop it explicitly.
+	 */
+	hid_hw_stop(hdev);
+
+	if (data->input2)
+		input_unregister_device(data->input2);
+}
+
 static const struct hid_device_id alps_id[] = {
 	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY,
 		USB_VENDOR_ID_ALPS_JP, HID_DEVICE_ID_ALPS_U1_DUAL) },
@@ -845,6 +863,7 @@ static struct hid_driver alps_driver = {
 	.input_configured	= alps_input_configured,
 	.resume			= pm_ptr(alps_post_resume),
 	.reset_resume		= pm_ptr(alps_post_reset),
+	.remove			= alps_remove,
 };
 
 module_hid_driver(alps_driver);
-- 
2.25.1