mfd: max77693: Fix possible NULL pointer dereference on i2c_new_dummy error

commit ad09dd6a1f5d6244bd89314015af506ba7f9810a upstream.

During probe the driver allocates dummy I2C devices for MUIC and haptic
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 devm_regmap_init_i2c() and i2c_unregister_device().

If i2c_new_dummy() fails for MUIC or haptic devices, fail also the probe
for main MFD driver.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/mfd/max77693.c b/drivers/mfd/max77693.c
index 9e60fed5ff82..299970f99588 100644
--- a/drivers/mfd/max77693.c
+++ b/drivers/mfd/max77693.c
@@ -149,9 +149,18 @@ static int max77693_i2c_probe(struct i2c_client *i2c,
                 dev_info(max77693->dev, "device ID: 0x%x\n", reg_data);
 
         max77693->muic = i2c_new_dummy(i2c->adapter, I2C_ADDR_MUIC);
+        if (!max77693->muic) {
+                dev_err(max77693->dev, "Failed to allocate I2C device for MUIC\n");
+                return -ENODEV;
+        }
         i2c_set_clientdata(max77693->muic, max77693);
 
         max77693->haptic = i2c_new_dummy(i2c->adapter, I2C_ADDR_HAPTIC);
+        if (!max77693->haptic) {
+                dev_err(max77693->dev, "Failed to allocate I2C device for Haptic\n");
+                ret = -ENODEV;
+                goto err_i2c_haptic;
+        }
         i2c_set_clientdata(max77693->haptic, max77693);
 
         /*
@@ -187,8 +196,9 @@ err_mfd:
         max77693_irq_exit(max77693);
 err_irq:
 err_regmap_muic:
-        i2c_unregister_device(max77693->muic);
         i2c_unregister_device(max77693->haptic);
+err_i2c_haptic:
+        i2c_unregister_device(max77693->muic);
         return ret;
 }