linux-kernel - [PATCH for 4.9 56/59] HID: wacom: release the resources before leaving despite devm

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Message-ID: <20170914155051.8289-56-alexander.levin@verizon.com>
Date:   Thu, 14 Sep 2017 15:51:20 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Jiri Kosina <jkosina@...e.cz>,
        "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
Subject: [PATCH for 4.9 56/59] HID: wacom: release the resources before
 leaving despite devm

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>
---
 drivers/hid/wacom_sys.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 0c535d0f3b95..53ac19b3727a 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -2433,6 +2433,8 @@ static void wacom_remove(struct hid_device *hdev)
 	if (hdev->bus == BUS_BLUETOOTH)
 		device_remove_file(&hdev->dev, &dev_attr_speed);
 
+	wacom_release_resources(wacom);
+
 	hid_set_drvdata(hdev, NULL);
 }
 
-- 
2.11.0