[3.11.y.z extended stable] Patch "mfd: max77686: Fix possible NULL pointer dereference on i2c_new_dummy error" has been added to staging queue

[Luis Henriques]

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

    mfd: max77686: Fix possible NULL pointer dereference on i2c_new_dummy error

to the linux-3.11.y-queue branch of the 3.11.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-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 20284ca7f2064a63dd10e2a4e6b2aeb9a8ca4425 Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <k.kozlowski at samsung.com>
Date: Tue, 11 Feb 2014 11:03:31 +0100
Subject: mfd: max77686: Fix possible NULL pointer dereference on i2c_new_dummy
 error

commit b9e183a1d495cd65412abe0f9df19b151716bfe7 upstream.

During probe the driver allocates dummy I2C device for RTC 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 i2c_unregister_device().

If i2c_new_dummy() fails for RTC 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: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/mfd/max77686.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mfd/max77686.c b/drivers/mfd/max77686.c
index 541b240..f50e03f 100644
--- a/drivers/mfd/max77686.c
+++ b/drivers/mfd/max77686.c
@@ -120,6 +120,10 @@ static int max77686_i2c_probe(struct i2c_client *i2c,
 		dev_info(max77686->dev, "device found\n");

 	max77686->rtc = i2c_new_dummy(i2c->adapter, I2C_ADDR_RTC);
+	if (!max77686->rtc) {
+		dev_err(max77686->dev, "Failed to allocate I2C device for RTC\n");
+		return -ENODEV;
+	}
 	i2c_set_clientdata(max77686->rtc, max77686);

 	max77686_irq_init(max77686);
--
1.9.1