[PATCH] github: Reduce ASLR entropy to be compatible with asan in llvm 14.

[David Marchand]

On Tue, Mar 12, 2024 at 3:53 PM Aaron Conole <aconole at redhat.com> wrote:
>
> GitHub recently started using newer Ubuntu 22.04 LTS container images,
> versioned 20240310.1.0 which use 32-bit entropy for ASLR:
>
>   $ sudo sysctl -a | grep vm.mmap.rnd
>   vm.mmap_rnd_bits = 32
>   vm.mmap_rnd_compat_bits = 16
>
> This breaks builds (such as the one at
> https://github.com/DPDK/dpdk/actions/runs/8234334617/job/22515850325) by
> causing a random segfault when ASAN is used, because older ASAN gets
> confused by memory mappings and crashes.
>
> The issue is fixed in newer releases of LLVM:
>   https://github.com/llvm/llvm-project/commit/fb77ca05ffb4f8e666878f2f6718a9fb4d686839
>   https://reviews.llvm.org/D148280
>
> But these are not available in Ubuntu 22.04 image.
>
> This should be fixed by GitHub, but until new images are available
> reducing ASLR entropy manually to 28 bits to make builds work.
>
> Reported-at: https://github.com/actions/runner-images/issues/9491
> Signed-off-by: Aaron Conole <aconole at redhat.com>
> Suggested-by: Ilya Maximets <i.maximets at ovn.org>

Thanks Aaron, I applied this workaround for now.

Heads up to subtree maintainers.
We have some false positive test failures in GHA for the past days.
Please rebase to DPDK main repository or pick this fix in your trees.


Thanks.

-- 
David Marchand