diff options
| author | Bastien Nocera <hadess@hadess.net> | 2019-06-27 09:20:45 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-31 07:28:53 +0200 |
| commit | 44b2e647a517161a96865c028707d984d4d169fb (patch) | |
| tree | 34256be5f8455613b29abc6c9dfe3a33a23931e3 | |
| parent | ad2012d96a37f9ab3faaa5795039f296ebf7db23 (diff) | |
iio: iio-utils: Fix possible incorrect mask calculation
[ Upstream commit 208a68c8393d6041a90862992222f3d7943d44d6 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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)) { |