Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 34eee70a authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Jonathan Cameron
Browse files

staging: iio: ad5933: avoid uninitialized variable in error case 

The ad5933_i2c_read function returns an error code to indicate
whether it could read data or not. However ad5933_work() ignores
this return code and just accesses the data unconditionally,
which gets detected by gcc as a possible bug:

drivers/staging/iio/impedance-analyzer/ad5933.c: In function 'ad5933_work':
drivers/staging/iio/impedance-analyzer/ad5933.c:649:16: warning: 'status' may be used uninitialized in this function [-Wmaybe-uninitialized]

This adds minimal error handling so we only evaluate the
data if it was correctly read.

Link: https://patchwork.kernel.org/patch/8110281/


Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent e866dd8a

drivers/staging/iio/impedance-analyzer/ad5933.c

+10 −7
Original line number Diff line number Diff line
@@ -655,6 +655,7 @@ static void ad5933_work(struct work_struct *work) 
	__be16 buf[2];

	int val[2];

	unsigned char status;

	int ret;



	mutex_lock(&indio_dev->mlock);

	if (st->state == AD5933_CTRL_INIT_START_FREQ) {
@@ -662,19 +663,22 @@ static void ad5933_work(struct work_struct *work) 
		ad5933_cmd(st, AD5933_CTRL_START_SWEEP);

		st->state = AD5933_CTRL_START_SWEEP;

		schedule_delayed_work(&st->work, st->poll_time_jiffies);

		mutex_unlock(&indio_dev->mlock);

		return;

		goto out;

	}



	ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);

	ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);

	if (ret)

		goto out;



	if (status & AD5933_STAT_DATA_VALID) {

		int scan_count = bitmap_weight(indio_dev->active_scan_mask,

					       indio_dev->masklength);

		ad5933_i2c_read(st->client,

		ret = ad5933_i2c_read(st->client,

				test_bit(1, indio_dev->active_scan_mask) ?

				AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,

				scan_count * 2, (u8 *)buf);

		if (ret)

			goto out;



		if (scan_count == 2) {

			val[0] = be16_to_cpu(buf[0]);
@@ -686,8 +690,7 @@ static void ad5933_work(struct work_struct *work) 
	} else {

		/* no data available - try again later */

		schedule_delayed_work(&st->work, st->poll_time_jiffies);

		mutex_unlock(&indio_dev->mlock);

		return;

		goto out;

	}



	if (status & AD5933_STAT_SWEEP_DONE) {
@@ -700,7 +703,7 @@ static void ad5933_work(struct work_struct *work) 
		ad5933_cmd(st, AD5933_CTRL_INC_FREQ);

		schedule_delayed_work(&st->work, st->poll_time_jiffies);

	}



out:

	mutex_unlock(&indio_dev->mlock);

}