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From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Fri, 28 Apr 2023 10:20:15 -0700
Message-ID: <CAEf4BzbOCHkBJq5OFNtwcbFWVjZBosECiYx_dLgnNYTX_MdAaA@mail.gmail.com>
Subject: Re: [PATCH 0/3] Dynptr Verifier Adjustments
To:     "Jose E. Marchesi" <jose.marchesi@oracle.com>
Cc:     Daniel Rosenberg <drosen@google.com>, bpf@vger.kernel.org,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        John Fastabend <john.fastabend@gmail.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Shuah Khan <shuah@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Joanne Koong <joannelkoong@gmail.com>,
        Mykola Lysenko <mykolal@fb.com>, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, kernel-team@android.com
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On Fri, Apr 28, 2023 at 2:04=E2=80=AFAM Jose E. Marchesi
<jose.marchesi@oracle.com> wrote:
>
>
> > On Thu, Apr 27, 2023 at 4:36=E2=80=AFPM Daniel Rosenberg <drosen@google=
.com> wrote:
> >>
> >> On Wed, Apr 26, 2023 at 4:39=E2=80=AFPM Andrii Nakryiko
> >> <andrii.nakryiko@gmail.com> wrote:
> >> >
> >> > Don't know, show the sequence of commands you are running?
> >> >
> >> > I have linux source in ~/linux, and KBUILD_OUTPUT set to
> >> > ~/linux-build/default. And it only takes this:
> >> >
> >> > $ cd ~/linux
> >> > $ make -j90 # build kernel
> >> > $ cd tools/testing/selftests/bpf
> >> > $ make -j90 # build selftests
> >> >
> >> > And that's it.
> >>
> >> I've tried the same, modulo some paths. I'm pretty sure it's version
> >> related at this point.
> >> The current issue I'm seeing is "error: indirect call in function,
> >> which are not supported by eBPF" when using GCC-BPF for
> >> progs/bind4_prog.c
> >
> > I don't think GCC-BPF is able to compile selftests properly just yet.
> > So I guess the problem is that you do have some version of gcc-bpf in
> > the system and selftest's Makefile tries to build gcc variants of
> > test_progs? That's bad (I don't have GCC-BPF locally, and everyone
> > else apparently as well).
> >
> > So for now just `make BPF_GCC=3D` ? CC'ing Jose, we should probably
> > agree on some criteria of "GCC-BPF is really capable of building
> > selftests" and adjust Makefile to only attempt GCC BPF build in that
> > case.
>
> Being able to run the selftests is our goal at the moment, but we are
> not there yet, no.
>
> What about making the kernel build system to emit a visible warning
> before it builds the GCC variants of the tests programs?  Something like
> "this is experimental and will likely fail".

Given gcc-bpf can't build selftests right now, should we just disable
it until there is a version on which gcc-bpf works? We can make it
such that you can force it to build using gcc-bpf (make USE_GCC_BPF=3D1
or something).

>
> >>
> >> Currently using clang 16.0.0 and gcc 12.2.0-14.
> >> I did manage to get it to build by just commenting out TEST_GEN_PROGS
> >> +=3D test_progs-bpf_gcc