Subject: FAILED: patch "[PATCH] HID: alps: unregister DualPoint Stick input device on remove" failed to apply to 5.15-stable tree
To: chenchangcheng@kylinos.cn,jkosina@suse.com
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Tue, 29 Sep 2026 10:43:59 +0200
Message-ID: <2026092958-confirm-underfed-6c0b@gregkh>
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The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x aa9dde93e05a837645fdfd577eea71f0733f0694
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026092958-confirm-underfed-6c0b@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:


thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From aa9dde93e05a837645fdfd577eea71f0733f0694 Mon Sep 17 00:00:00 2001
From: Chen Changcheng <chenchangcheng@kylinos.cn>
Date: Fri, 14 Aug 2026 15:06:20 +0800
Subject: [PATCH] HID: alps: unregister DualPoint Stick input device on remove

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>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

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);