I'm using clang 10.0.0 and configuring with with `configure --enable-gpl --enable-libass --enable-libfdk-aac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-librtmp --enable-libtheora --enable-libvorbis --enable-libopus --enable-libx264 --enable-libvpx --enable-nonfree --enable-version3 --disable-optimizations --disable-stripping --enable-debug=3 --toolchain=clang-usan` (plus `--extra-cflags=-fno-sanitize-recover=pointer-overflow --extra-ldflags=-fno-sanitize-recover=pointer-overflow` to crash when we run into the UB)
When I run `make fate -j 12 SAMPLES=fate-suite`, several tests (e.g. api-mjpeg-codec-param) fail with something like the following in the error logs: libavutil/imgutils.c:139:29: runtime error: applying non-zero offset 131072 to null pointer SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior libavutil/imgutils.c:139:29 in It looks like this check was added in clang 10 ( https://reviews.llvm.org/D67122) On Thu, Jul 2, 2020 at 8:06 AM Michael Niedermayer <mich...@niedermayer.cc> wrote: > On Wed, Jul 01, 2020 at 11:14:13AM -0700, Brian Kim wrote: > > While running under Clang's UndefinedBehaviorSanitizer, I found a few > > places where av_image_fill_pointers is called before buffers for the > image > > are allocated, so ptr is passed in as NULL. > > > > This leads to (currently harmless) UB when the plane sizes are added to > the > > null pointer, so I was wondering if there was interest in avoiding it? > > > > I've attached a patch to expose some extra utilities and avoid passing in > > the null pointer, but is this an appropriate way to work around it? > > how can these cases be reproduced ? > > thx > > [...] > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > The smallest minority on earth is the individual. Those who deny > individual rights cannot claim to be defenders of minorities. - Ayn Rand > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
