[PATCH 3.4 08/43] mfd: max8925: Fix possible NULL pointer dereference on i2c_new_dummy error

From: Greg Kroah-Hartman
Date: Sun May 04 2014 - 11:53:44 EST


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

------------------

From: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>

commit 96cf3dedc491d2f1f66cc26217f2b06b0c7b6797 upstream.

During probe the driver allocates dummy I2C devices for RTC and ADC
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 or ADC devices, 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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/mfd/max8925-i2c.c | 9 +++++++++
1 file changed, 9 insertions(+)

--- a/drivers/mfd/max8925-i2c.c
+++ b/drivers/mfd/max8925-i2c.c
@@ -156,9 +156,18 @@ static int __devinit max8925_probe(struc
mutex_init(&chip->io_lock);

chip->rtc = i2c_new_dummy(chip->i2c->adapter, RTC_I2C_ADDR);
+ if (!chip->rtc) {
+ dev_err(chip->dev, "Failed to allocate I2C device for RTC\n");
+ return -ENODEV;
+ }
i2c_set_clientdata(chip->rtc, chip);

chip->adc = i2c_new_dummy(chip->i2c->adapter, ADC_I2C_ADDR);
+ if (!chip->adc) {
+ dev_err(chip->dev, "Failed to allocate I2C device for ADC\n");
+ i2c_unregister_device(chip->rtc);
+ return -ENODEV;
+ }
i2c_set_clientdata(chip->adc, chip);

device_init_wakeup(&client->dev, 1);


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