Re: [PATCH bpf-next] selftests/bpf: Fix selftest compilation on clang 11

From: Daniel Borkmann <daniel@iogearbox.net>
To: KP Singh <kpsingh@kernel.org>, Jiri Olsa <jolsa@redhat.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andriin@fb.com>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Brendan Jackman <jackmanb@google.com>,
	KP Singh <kpsingh@google.com>
Subject: Re: [PATCH bpf-next] selftests/bpf: Fix selftest compilation on clang 11
Date: Thu, 10 Dec 2020 17:36:51 +0100	[thread overview]
Message-ID: <d0dbe550-5d75-29bd-cded-7ecd86f41719@iogearbox.net> (raw)
In-Reply-To: <CANA3-0dvt3FH8=ZYO7CfW0YKeQemNcsP76j441wW31-WE1_o4A@mail.gmail.com>

On 12/10/20 5:28 PM, KP Singh wrote:
> On Thu, Dec 10, 2020 at 5:18 PM Jiri Olsa <jolsa@redhat.com> wrote:
[...]
>>> It's hard and time-consuming enough to develop these features, I'd
>>> rather keep selftests simpler, more manageable, and less brittle by
>>> not having excessive amount of feature detection and skipped
>>> selftests. I think that's the case for BPF atomics as well, btw (cc'ed
>>> Yonghong and Brendan).
>>>
>>> To alleviate some of the pain of setting up the environment, one way
>>> would be to provide script and/or image to help bring up qemu VM for
>>> easier testing. To that end, KP Singh (cc'ed) was able to re-use
>>> libbpf CI's VM setup and make it easier for local development. I hope
>>> he can share this soon.
> 
> I will clean it up and share it asap and send it as an RFC which
> adds it to tools/testing/selftests/bpf

Thanks!

> We can discuss on the RFC as to where the script would finally end up
> but I think it would save a lot of time/back-and-forth if developers could
> simply check:
> 
>    "Does my change break the BPF CI?"

I'd love to have a Dockerfile under tools/testing/selftests/bpf/ that
replicates the CI env (e.g. busybox, nightly llvm, pahole git, etc) where
we could have quay.io job auto-build this for bpf / bpf-next tree e.g. from a
GH mirror. This would then allow to mount the local kernel tree as a volume
into the container for easy compilation & test access for everyone where we
then don't need all these workarounds like in this patch anymore.

Thanks,
Daniel