linux-kernel - [PATCH 7/7] mfd: max8998: Fix possible NULL pointer dereference on i2c_new

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Date:	Tue, 11 Feb 2014 11:03:35 +0100
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Sangbeom Kim <sbkim73@...sung.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	Lee Jones <lee.jones@...aro.org>, linux-kernel@...r.kernel.org,
	linux-samsung-soc@...r.kernel.org
Cc:	Kyungmin Park <kyungmin.park@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	stable@...r.kernel.org
Subject: [PATCH 7/7] mfd: max8998: Fix possible NULL pointer dereference on
 i2c_new_dummy error

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@...sung.com>
Cc: stable@...r.kernel.org
---
 drivers/mfd/max8998.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mfd/max8998.c b/drivers/mfd/max8998.c
index 612ca404e150..61ea1826f8b4 100644
--- a/drivers/mfd/max8998.c
+++ b/drivers/mfd/max8998.c
@@ -215,6 +215,10 @@ static int max8998_i2c_probe(struct i2c_client *i2c,
 	mutex_init(&max8998->iolock);
 
 	max8998->rtc = i2c_new_dummy(i2c->adapter, RTC_I2C_ADDR);
+	if (!max8998->rtc) {
+		dev_err(&i2c->dev, "Failed to allocate I2C device for RTC\n");
+		return -ENODEV;
+	}
 	i2c_set_clientdata(max8998->rtc, max8998);
 
 	max8998_irq_init(max8998);
-- 
1.7.9.5

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