[PATCH] iio: ssp_sensors: avoid uninitialized variable usage

Arnd Bergmann
2019-03-22T14:10:09Z

clang points out that 'calculated_time' is only sometimes
initialized here, which leads to incorrect data being
passed into another function:

drivers/iio/common/ssp_sensors/ssp_iio.c:95:6: error: variable 'calculated_time' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
if (indio_dev->scan_timestamp) {
^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/iio/common/ssp_sensors/ssp_iio.c:102:9: note: uninitialized use occurs here
calculated_time);
^~~~~~~~~~~~~~~
drivers/iio/common/ssp_sensors/ssp_iio.c:95:2: note: remove the 'if' if its condition is always true
if (indio_dev->scan_timestamp) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/iio/common/ssp_sensors/ssp_iio.c:84:25: note: initialize the variable 'calculated_time' to silence this warning
int64_t calculated_time;
^
The data is subsequently ignored by iio_push_to_buffers_with_timestamp(),
but the warning still feels legitimate and to work around it, we can
initialize the time in the other case.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18501
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/iio/common/ssp_sensors/ssp_iio.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/iio/common/ssp_sensors/ssp_iio.c b/drivers/iio/common/ssp_sensors/ssp_iio.c
index 645f2e3975db..81e8f4844c90 100644
--- a/drivers/iio/common/ssp_sensors/ssp_iio.c
+++ b/drivers/iio/common/ssp_sensors/ssp_iio.c
@@ -96,6 +96,8 @@ int ssp_common_process_data(struct iio_dev *indio_dev, void *buf,
memcpy(&time, &((char *)buf)[len], SSP_TIME_SIZE);
calculated_time =
timestamp + (int64_t)le32_to_cpu(time) * 1000000;
+ } else {
+ calculated_time = 0;
}

return iio_push_to_buffers_with_timestamp(indio_dev, spd->buffer,
--
2.20.0