Hello Jagath Jog J,
The patch 961db2da159d: "iio: accel: bma400: Add support for single
and double tap events" from Aug 31, 2022, leads to the following
Smatch static checker warning:
drivers/iio/accel/bma400_core.c:1287 bma400_tap_event_en()
error: uninitialized symbol 'field_value'.
drivers/iio/accel/bma400_core.c
1242 static int bma400_tap_event_en(struct bma400_data *data,
1243 enum iio_event_direction dir, int state)
1244 {
1245 unsigned int mask, field_value;
^^^^^^^^^^^^
This is uninitialized.
1246 int ret;
1247
1248 /*
1249 * Tap interrupts can be configured only in normal mode.
1250 * See table in section 4.3 "Power modes - performance modes" of
1251 * datasheet v1.2.
1252 */
1253 if (data->power_mode != POWER_MODE_NORMAL)
1254 return -EINVAL;
1255
1256 /*
1257 * Tap interrupts are operating with a data rate of 200Hz.
1258 * See section 4.7 "Tap sensing interrupt" in datasheet v1.2.
1259 */
1260 if (data->sample_freq.hz != 200 && state) {
1261 dev_err(data->dev, "Invalid data rate for tap interrupts.\n");
1262 return -EINVAL;
1263 }
1264
1265 ret = regmap_update_bits(data->regmap, BMA400_INT12_MAP_REG,
1266 BMA400_S_TAP_MSK,
1267 FIELD_PREP(BMA400_S_TAP_MSK, state));
1268 if (ret)
1269 return ret;
1270
1271 switch (dir) {
1272 case IIO_EV_DIR_SINGLETAP:
1273 mask = BMA400_S_TAP_MSK;
1274 set_mask_bits(&field_value, BMA400_S_TAP_MSK,
^^^^^^^^^^^^
Smatch ought to print a warning here but these macros use a bunch of
*(&(*(&field_value))) permutations that confuse Smatch. Smatch does
not print a warning if you're just taking the address of a variable.
This initializes BIT(3)? I believe that KMSan will detect this as a bug
an issue a warning here.
1275 FIELD_PREP(BMA400_S_TAP_MSK, state));
1276 break;
1277 case IIO_EV_DIR_DOUBLETAP:
1278 mask = BMA400_D_TAP_MSK;
1279 set_mask_bits(&field_value, BMA400_D_TAP_MSK,
1280 FIELD_PREP(BMA400_D_TAP_MSK, state));
1281 break;
1282 default:
1283 return -EINVAL;
1284 }
1285
1286 ret = regmap_update_bits(data->regmap, BMA400_INT_CONFIG1_REG, mask,
--> 1287 field_value);
This uses BIT(3). The function only cares about BIT(3) but the other
bits are uninitialized.
1288 if (ret)
1289 return ret;
1290
1291 set_mask_bits(&data->tap_event_en_bitmask, mask, field_value);
1292
1293 return 0;
1294 }
regards,
dan carpenter
