[llvm-dev] Non-determinism in libFuzzer tests on AArch64

[Grang, Mandeep Singh via llvm-dev]

I have worked on fixing/uncovering non-determinism in llvm and clang [1] 
[2] [3] [4]. The main causes there were iteration of unordered 
containers, hashing on pointers and using std::sort on equal elements. 
Although I am not sure if the libfuzzer issues are the same/similar.

[1] http://lists.llvm.org/pipermail/llvm-dev/2016-November/107098.html

[2] http://lists.llvm.org/pipermail/llvm-dev/2017-July/115025.html

[3] http://lists.llvm.org/pipermail/llvm-dev/2017-August/116975.html

[4] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118639.html

--Mandeep

On 3/22/2019 8:01 AM, Diana Picus via llvm-dev wrote:
> Hi,
>
> I've seen this issue pop up on the mailing list a couple of times
> before with no resolution [1][2][3].
>
> It has been getting really bad for our AArch64 buildbots lately. You
> can see a few examples at the end of my email [4], but we have the
> same failures on a couple of other bots as well.
>
> Does anyone have any idea how to reproduce / investigate these issues?
> If not, is it reasonable to mark the tests as unsupported on AArch64?
>
> Thanks,
> Diana
>
> [1] https://lists.llvm.org/pipermail/llvm-dev/2018-June/124334.html
> [2] http://lists.llvm.org/pipermail/llvm-dev/2019-January/128861.html
> [3] https://lists.llvm.org/pipermail/llvm-dev/2018-November/127701.html
> [4] clang-cmake-aarch64-lld failures:
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6264
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6262
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6260
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6255
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6253
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6250
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6247
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6245
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6237
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6235
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6229
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev