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| author | Bastien Nocera <hadess@hadess.net> | 2019-06-27 09:20:45 +0200 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2019-06-27 20:38:19 +0100 |
| commit | 208a68c8393d6041a90862992222f3d7943d44d6 (patch) | |
| tree | 6b656dd51d2fb1178265b1820e9baf5a362a2201 /tools/iio | |
| parent | def914a4c3899b6b3705c8ea67d29972f5652a14 (diff) | |
| download | linux-208a68c8393d6041a90862992222f3d7943d44d6.tar.bz2 | |
iio: iio-utils: Fix possible incorrect mask calculation
On some machines, iio-sensor-proxy was returning all 0's for IIO sensor
values. It turns out that the bits_used for this sensor is 32, which makes
the mask calculation:
*mask = (1 << 32) - 1;
If the compiler interprets the 1 literals as 32-bit ints, it generates
undefined behavior depending on compiler version and optimization level.
On my system, it optimizes out the shift, so the mask value becomes
*mask = (1) - 1;
With a mask value of 0, iio-sensor-proxy will always return 0 for every axis.
Avoid incorrect 0 values caused by compiler optimization.
See original fix by Brett Dutro <brett.dutro@gmail.com> in
iio-sensor-proxy:
https://github.com/hadess/iio-sensor-proxy/commit/9615ceac7c134d838660e209726cd86aa2064fd3
Signed-off-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'tools/iio')
| -rw-r--r-- | tools/iio/iio_utils.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c index 7a6d61c6c012..55272fef3b50 100644 --- a/tools/iio/iio_utils.c +++ b/tools/iio/iio_utils.c @@ -159,9 +159,9 @@ int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used, *be = (endianchar == 'b'); *bytes = padint / 8; if (*bits_used == 64) - *mask = ~0; + *mask = ~(0ULL); else - *mask = (1ULL << *bits_used) - 1; + *mask = (1ULL << *bits_used) - 1ULL; *is_signed = (signchar == 's'); if (fclose(sysfsfp)) { |