On 7/19/24 13:55, Dan Carpenter wrote:
Hello Eduardo Valentin,
Commit 3aa74796cfd0 ("hwmon: (pmbus) Register with thermal for
PSC_TEMPERATURE") from Apr 28, 2022 (linux-next), leads to the
following Smatch static checker warning:
drivers/hwmon/pmbus/pmbus_core.c:1375 pmbus_add_sensor()
error: we previously assumed 'type' could be null (see line 1347)
drivers/hwmon/pmbus/pmbus_core.c
1331 static struct pmbus_sensor *pmbus_add_sensor(struct pmbus_data *data,
1332 const char *name, const char *type,
1333 int seq, int page, int phase,
1334 int reg,
1335 enum pmbus_sensor_classes class,
1336 bool update, bool readonly,
1337 bool convert)
1338 {
1339 struct pmbus_sensor *sensor;
1340 struct device_attribute *a;
1341
1342 sensor = devm_kzalloc(data->dev, sizeof(*sensor), GFP_KERNEL);
1343 if (!sensor)
1344 return NULL;
1345 a = &sensor->attribute;
1346
1347 if (type)
^^^^
This code assumes type can be NULL
1348 snprintf(sensor->name, sizeof(sensor->name), "%s%d_%s",
1349 name, seq, type);
1350 else
1351 snprintf(sensor->name, sizeof(sensor->name), "%s%d",
1352 name, seq);
1353
1354 if (data->flags & PMBUS_WRITE_PROTECTED)
1355 readonly = true;
1356
1357 sensor->page = page;
1358 sensor->phase = phase;
1359 sensor->reg = reg;
1360 sensor->class = class;
1361 sensor->update = update;
1362 sensor->convert = convert;
1363 sensor->data = -ENODATA;
1364 pmbus_dev_attr_init(a, sensor->name,
1365 readonly ? 0444 : 0644,
1366 pmbus_show_sensor, pmbus_set_sensor);
1367
1368 if (pmbus_add_attribute(data, &a->attr))
1369 return NULL;
1370
1371 sensor->next = data->sensors;
1372 data->sensors = sensor;
1373
1374 /* temperature sensors with _input values are registered with thermal */
--> 1375 if (class == PSC_TEMPERATURE && strcmp(type, "input") == 0)
^^^^
Unchecked dereference
It is only NULL for PSC_PWM, never for PSC_TEMPERATURE. We could add a check to
make the static checker happy but it won't make a practical difference.
Guenter
