[PATCH 3.10 23/86] mfd: 88pm860x: Fix possible NULL pointer dereference on i2c_new_dummy error

From: Greg Kroah-Hartman
Date: Sun May 04 2014 - 12:12:44 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>

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@xxxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/mfd/88pm860x-core.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/mfd/88pm860x-core.c
+++ b/drivers/mfd/88pm860x-core.c
@@ -1179,6 +1179,11 @@ static int pm860x_probe(struct i2c_clien
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");
+ return -ENODEV;
+ }
chip->regmap_companion = regmap_init_i2c(chip->companion,
&pm860x_regmap_config);
if (IS_ERR(chip->regmap_companion)) {


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