base: dd: fix error return code of driver_sysfs_add()

When device_create_file() fails and returns a non-zero value,
no error return code of driver_sysfs_add() is assigned.
To fix this bug, ret is assigned with the return value of
device_create_file(), and then ret is checked.
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20210324023405.12465-1-baijiaju1990@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/dd.c

@@ -415,8 +415,11 @@ static int driver_sysfs_add(struct device *dev)
 	if (ret)
 		goto rm_dev;
 
-	if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump ||
-	    !device_create_file(dev, &dev_attr_coredump))
+	if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump)
+		return 0;
+
+	ret = device_create_file(dev, &dev_attr_coredump);
+	if (!ret)
 		return 0;
 
 	sysfs_remove_link(&dev->kobj, "driver");