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| author | Wan-Teh Chang <wtc@google.com> | 2016-12-07 16:16:02 -0800 |
|---|---|---|
| committer | Vittorio Giovara <vittorio.giovara@gmail.com> | 2016-12-08 15:53:58 -0500 |
| commit | 2170017a1cd033b6f28e16476921022712a522d8 (patch) | |
| tree | cfcbe102ef4c0fcddd52e2b51b9fca5a850db146 /compat | |
| parent | d5759701a82926059ae3e2530805e900041a5419 (diff) | |
| download | ffmpeg-streaming-2170017a1cd033b6f28e16476921022712a522d8.zip ffmpeg-streaming-2170017a1cd033b6f28e16476921022712a522d8.tar.gz | |
avutil: fix data race in av_get_cpu_flags()
Make the one-time initialization in av_get_cpu_flags() thread-safe. The
static variables |flags|, |cpuflags_mask|, and |checked| in
libavutil/cpu.c are read and written using normal load and store
operations. These are considered as data races. The fix is to use atomic
load and store operations.
Remove the |checked| variable because the invalid value of -1 for
|flags| can be used to indicate the same condition. Rename |flags| to
|cpu_flags| and move it to file scope.
The fix can be verified by running the libavutil/tests/cpu_init.c test
program under ThreadSanitizer:
./configure --toolchain=clang-tsan
make libavutil/tests/cpu_init
libavutil/tests/cpu_init
There should be no warnings from ThreadSanitizer.
Co-author: Dmitry Vyukov of Google, who suggested the data race fix.
Signed-off-by: Wan-Teh Chang <wtc@google.com>
Diffstat (limited to 'compat')
0 files changed, 0 insertions, 0 deletions
