gpio: max732x: Fix possible NULL pointer dereference on i2c_new_dummy error

In max732x_probe() driver allocates dummy I2C device (if number of ports
is greater than 8) with i2c_new_dummy() but it does not check the return
value of this call.

In case of error (i2c_new_device(): memory allocation failure or I2C
address cannot be used) this function returns NULL which is later
dereferenced by i2c_smbus_read_byte() (called from max732x_readb()).

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-max732x.c b/drivers/gpio/gpio-max732x.c
index 74432daaf6564c21477cb7e739ec3429231f65fc..7c36f2b0983d89b355c047d087781df24db4ce03 100644 (file)
--- a/drivers/gpio/gpio-max732x.c
+++ b/drivers/gpio/gpio-max732x.c
@@ -622,6 +622,13 @@ static int max732x_probe(struct i2c_client *client,
                goto out_failed;
        }
 
+       if (nr_port > 8 && !chip->client_dummy) {
+               dev_err(&client->dev,
+                       "Failed to allocate second group I2C device\n");
+               ret = -ENODEV;
+               goto out_failed;
+       }
+
        mutex_init(&chip->lock);
 
        max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);