[PATCH 3.12 041/182] mfd: max8998: Fix possible NULL pointer dereference on i2c_new_dummy error

[Jiri Slaby]

From: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>

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

===============

commit ed26f87b9f71693a1d1ee85f5e6209601505080f 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@xxxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/mfd/max8998.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mfd/max8998.c b/drivers/mfd/max8998.c
index fe6332dcabee..25e131a0840a 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);
-- 
1.9.3

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