mfd: 88pm860x: Fix possible NULL pointer dereference on i2c_new_dummy error

commit 159ce52a6b777fc82fa0b51c7440e25f9e4c6feb upstream.

During probe the driver allocates dummy I2C device for companion chip
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 used
by regmap_init_i2c().

If i2c_new_dummy() fails for companion device, fail also the probe for
main MFD driver.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[bwh: Backported to 3.2:
 - Adjust filename, context
 - Add kfree() before return, as driver is not using managed allocations]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/mfd/88pm860x-i2c.c b/drivers/mfd/88pm860x-i2c.c
index e017dc88622ada48f145457585e5fc376a6d155e..f035dd3c7a095cda2c2f0d57f54e11e71d6a3f71 100644 (file)
--- a/drivers/mfd/88pm860x-i2c.c
+++ b/drivers/mfd/88pm860x-i2c.c
@@ -290,6 +290,12 @@ static int __devinit pm860x_probe(struct i2c_client *client,
                chip->companion_addr = pdata->companion_addr;
                chip->companion = i2c_new_dummy(chip->client->adapter,
                                                chip->companion_addr);
+               if (!chip->companion) {
+                       dev_err(&client->dev,
+                               "Failed to allocate I2C companion device\n");
+                       kfree(chip);
+                       return -ENODEV;
+               }
                i2c_set_clientdata(chip->companion, chip);
        }