We work around that as:
https://github.com/llvm/llvm-zorg/blob/95b6239a1e159342caf514cd7b3ab0eaf7996251/zorg/buildbot/builders/sanitizers/buildbot_functions.sh#L303

Would be nice to switch to llvm unwinder.

@petrhosek @ldionne I know you run check-cxx check-cxxabi with sanitizers. Which unwinder do you use?