linux-kernel - [PATCH 4.9 054/104] HID: wacom: release the resources before leaving despite devm

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Date:   Fri,  6 Oct 2017 10:51:32 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Jason Gerecke <jason.gerecke@...om.com>,
        Jiri Kosina <jkosina@...e.cz>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.9 054/104] HID: wacom: release the resources before leaving despite devm

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Benjamin Tissoires <benjamin.tissoires@...hat.com>


[ Upstream commit 5b779fc52020ac6f5beea31c5eafc3d25cf70dc1 ]

In the general case, the resources are properly released by devm without
needing to do anything. However, when unplugging the wireless receiver,
the kernel segfaults from time to time while calling devres_release_all().

I think in that case the resources attempt to access hid_get_drvdata(hdev)
which has been set to null while leaving wacom_remove().

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
Acked-by: Jason Gerecke <jason.gerecke@...om.com>
Signed-off-by: Jiri Kosina <jkosina@...e.cz>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/hid/wacom_sys.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -2433,6 +2433,8 @@ static void wacom_remove(struct hid_devi
 	if (hdev->bus == BUS_BLUETOOTH)
 		device_remove_file(&hdev->dev, &dev_attr_speed);
 
+	wacom_release_resources(wacom);
+
 	hid_set_drvdata(hdev, NULL);
 }