[3.8.y.z extended stable] Patch "mfd: 88pm860x: Fix possible NULL pointer dereference on i2c_new_dummy error" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

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

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.22.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 7c299cec3f22ae602c9424971aa3ca250a9057d2 Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <k.kozlowski at samsung.com>
Date: Tue, 11 Feb 2014 11:03:29 +0100
Subject: 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 at samsung.com>
Signed-off-by: Lee Jones <lee.jones at linaro.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/mfd/88pm860x-core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mfd/88pm860x-core.c b/drivers/mfd/88pm860x-core.c
index f304a09..238c7b0 100644
--- a/drivers/mfd/88pm860x-core.c
+++ b/drivers/mfd/88pm860x-core.c
@@ -1181,6 +1181,11 @@ static int 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");
+			return -ENODEV;
+		}
 		chip->regmap_companion = regmap_init_i2c(chip->companion,
 							&pm860x_regmap_config);
 		if (IS_ERR(chip->regmap_companion)) {
--
1.9.1