[bug report] hwmon: Add "label" attribute

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Paul Cercueil,

This is a semi-automatic email about new static checker warnings.

The patch 073c3ea6c530: "hwmon: Add "label" attribute" from Jan 10,
2022, leads to the following Smatch complaint:

    drivers/hwmon/hwmon.c:825 __hwmon_device_register()
    warn: variable dereferenced before check 'dev' (see line 810)

drivers/hwmon/hwmon.c
   809
   810		if (device_property_present(dev, "label")) {
                                            ^^^
The patch adds a new unchecked dereference

   811			err = device_property_read_string(dev, "label", &label);
   812			if (err < 0)
   813				goto free_hwmon;
   814	
   815			hwdev->label = kstrdup(label, GFP_KERNEL);
   816			if (hwdev->label == NULL) {
   817				err = -ENOMEM;
   818				goto free_hwmon;
   819			}
   820		}
   821	
   822		hwdev->name = name;
   823		hdev->class = &hwmon_class;
   824		hdev->parent = dev;
   825		hdev->of_node = dev ? dev->of_node : NULL;
                                ^^^
Existing code checked for NULL

   826		hwdev->chip = chip;
   827		dev_set_drvdata(hdev, drvdata);

regards,
dan carpenter