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From:   Kangjie Lu <kjlu@umn.edu>
To:     kjlu@umn.edu
Cc:     pakki001@umn.edu, Jonathan Cameron <jic23@kernel.org>,
        Hartmut Knaack <knaack.h@gmx.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        Stefan Agner <stefan@agner.ch>,
        Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] iio: max9611: fix a NULL pointer dereference
Date:   Fri,  8 Mar 2019 22:51:40 -0600
Message-Id: <20190309045141.8015-1-kjlu@umn.edu>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

of_match_device may return NULL when it fails, and in this case,
there will be a NULL pointer dereference. The fix returns
EINVAL when of_match_device returns NULL.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/iio/adc/max9611.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/max9611.c b/drivers/iio/adc/max9611.c
index 917223d5ff5b..531b6614ea29 100644
--- a/drivers/iio/adc/max9611.c
+++ b/drivers/iio/adc/max9611.c
@@ -524,13 +524,16 @@ static int max9611_probe(struct i2c_client *client,
 {
 	const char * const shunt_res_prop = "shunt-resistor-micro-ohms";
 	const struct device_node *of_node = client->dev.of_node;
-	const struct of_device_id *of_id =
-		of_match_device(max9611_of_table, &client->dev);
+	const struct of_device_id *of_id;
 	struct max9611_dev *max9611;
 	struct iio_dev *indio_dev;
 	unsigned int of_shunt;
 	int ret;
 
+	of_id = of_match_device(max9611_of_table, &client->dev);
+	if (!of_id)
+		return -EINVAL;
+
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*max9611));
 	if (!indio_dev)
 		return -ENOMEM;
-- 
2.17.1