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.

Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/max8998.c b/drivers/mfd/max8998.c
index 5d5e186b5d8bbbfed035725480fb85dc52a0fdb4..592db06098e69eabeb08c506cb3409c6d2ff2ca9 100644 (file)
--- 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);