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| author | Bastien Nocera <hadess@hadess.net> | 2019-06-27 09:20:45 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-31 07:24:43 +0200 |
| commit | 5d691a4b82ad0910e3b8824e992204f42a1d6131 (patch) | |
| tree | 2ffd78bf74c59720b39efa09d3639e184307800b /tools | |
| parent | fae39a0c5cd3e0e1c4508a7f3f862e482773cb03 (diff) | |
| download | linux-stable-5d691a4b82ad0910e3b8824e992204f42a1d6131.tar.gz linux-stable-5d691a4b82ad0910e3b8824e992204f42a1d6131.tar.bz2 linux-stable-5d691a4b82ad0910e3b8824e992204f42a1d6131.zip | |
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>
Diffstat (limited to 'tools')
| -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 a22b6e8fad46..7399eb7f1378 100644 --- a/tools/iio/iio_utils.c +++ b/tools/iio/iio_utils.c @@ -156,9 +156,9 @@ 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)) { |