[3.8.y.z extended stable] Patch "mfd: max8997: 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: max8997: 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 87589fc3b40a80c5363faafe59692dc1fd218088 Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <k.kozlowski at samsung.com>
Date: Tue, 11 Feb 2014 11:03:34 +0100
Subject: mfd: max8997: Fix possible NULL pointer dereference on i2c_new_dummy
 error

commit 97dc4ed3fa377ec91bb60ba98b70d645c2099384 upstream.

During probe the driver allocates dummy I2C devices for RTC, haptic and
MUIC with i2c_new_dummy() but it does not check the return value of this
calls.

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, haptic or MUIC devices, 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/max8997.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/mfd/max8997.c b/drivers/mfd/max8997.c
index 1471405..ea1defbc 100644
--- a/drivers/mfd/max8997.c
+++ b/drivers/mfd/max8997.c
@@ -218,10 +218,26 @@ static int max8997_i2c_probe(struct i2c_client *i2c,
 	mutex_init(&max8997->iolock);

 	max8997->rtc = i2c_new_dummy(i2c->adapter, I2C_ADDR_RTC);
+	if (!max8997->rtc) {
+		dev_err(max8997->dev, "Failed to allocate I2C device for RTC\n");
+		return -ENODEV;
+	}
 	i2c_set_clientdata(max8997->rtc, max8997);
+
 	max8997->haptic = i2c_new_dummy(i2c->adapter, I2C_ADDR_HAPTIC);
+	if (!max8997->haptic) {
+		dev_err(max8997->dev, "Failed to allocate I2C device for Haptic\n");
+		ret = -ENODEV;
+		goto err_i2c_haptic;
+	}
 	i2c_set_clientdata(max8997->haptic, max8997);
+
 	max8997->muic = i2c_new_dummy(i2c->adapter, I2C_ADDR_MUIC);
+	if (!max8997->muic) {
+		dev_err(max8997->dev, "Failed to allocate I2C device for MUIC\n");
+		ret = -ENODEV;
+		goto err_i2c_muic;
+	}
 	i2c_set_clientdata(max8997->muic, max8997);

 	pm_runtime_set_active(max8997->dev);
@@ -248,7 +264,9 @@ static int max8997_i2c_probe(struct i2c_client *i2c,
 err_mfd:
 	mfd_remove_devices(max8997->dev);
 	i2c_unregister_device(max8997->muic);
+err_i2c_muic:
 	i2c_unregister_device(max8997->haptic);
+err_i2c_haptic:
 	i2c_unregister_device(max8997->rtc);
 err:
 	kfree(max8997);
--
1.9.1