[PATCH] iio: max9611: fix a NULL pointer dereference

[Kangjie Lu]

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 <k...@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