From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
"Andrii Nakryiko" <andriin@fb.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
BPF-dev-list <bpf@vger.kernel.org>,
"Daniel Borkmann" <borkmann@iogearbox.net>,
"David Miller" <davem@davemloft.net>,
LKML <linux-kernel@vger.kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Anders Roxell" <anders.roxell@linaro.org>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
brouer@redhat.com
Subject: Re: Kernel 5.5.4 build fail for BPF-selftests with latest LLVM
Date: Wed, 19 Feb 2020 21:06:09 +0100 [thread overview]
Message-ID: <20200219210609.20a097fb@carbon> (raw)
In-Reply-To: <CAEf4BzaRAK6-7aCCVOA6hjTevKuxgvZZnHeVgdj_ZWNn8wibYQ@mail.gmail.com>
On Wed, 19 Feb 2020 10:38:45 -0800
Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> On Wed, Feb 19, 2020 at 10:29 AM Jesper Dangaard Brouer
> <brouer@redhat.com> wrote:
> >
> > On Wed, 19 Feb 2020 09:38:50 -0800
> > Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> >
> > > On Wed, Feb 19, 2020 at 9:04 AM Jesper Dangaard Brouer
> > > <brouer@redhat.com> wrote:
> > > >
> > > > On Wed, 19 Feb 2020 08:41:27 -0800
> > > > Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> > > >
> > > > > On Wed, Feb 19, 2020 at 4:30 AM Jesper Dangaard Brouer
> > > > > <brouer@redhat.com> wrote:
> > > > > >
> > > > > > I'm willing to help out, such that we can do either version or feature
> > > > > > detection, to either skip compiling specific test programs or at least
> > > > > > give users a proper warning of they are using a too "old" LLVM version.
> > > > > ...
> > > > > > progs/test_core_reloc_bitfields_probed.c:47:13: error: use of unknown builtin '__builtin_preserve_field_info' [-Wimplicit-function-declaration]
> > > > > > out->ub1 = BPF_CORE_READ_BITFIELD_PROBED(in, ub1);
> > > > >
> > > > > imo this is proper warning message already.
> > > >
> > > > This is an error, not a warning. The build breaks as the make process stops.
> > > >
> > >
> > > Latest Clang was a requirement for building and running all selftests
> > > for a long time now. There were few previous discussions on mailing
> > > list about this and each time the conclusion was the same: latest
> > > Clang is a requirement for BPF selftests.
> >
> > The latest Clang is 9.0.1, and it doesn't build with that.
>
> Latest as in "latest built from sources".
When I download a specific kernel release, how can I know what LLVM
git-hash or version I need (to use BPF-selftests)?
Do you think it is reasonable to require end-users to compile their own
bleeding edge version of LLVM, to use BPF-selftests?
I do hope that some end-users of BPF-selftests will be CI-systems.
That also implies that CI-system maintainers need to constantly do
"latest built from sources" of LLVM git-tree to keep up. Is that a
reasonable requirement when buying a CI-system in the cloud?
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2020-02-19 20:06 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 12:30 Kernel 5.5.4 build fail for BPF-selftests with latest LLVM Jesper Dangaard Brouer
2020-02-19 13:28 ` Greg Kroah-Hartman
2020-02-19 13:42 ` Jesper Dangaard Brouer
2020-02-19 18:12 ` Greg Kroah-Hartman
2020-02-19 19:40 ` Jesper Dangaard Brouer
2020-02-19 20:20 ` Greg Kroah-Hartman
2020-02-19 16:41 ` Alexei Starovoitov
2020-02-19 17:03 ` Jesper Dangaard Brouer
2020-02-19 17:38 ` Andrii Nakryiko
2020-02-19 18:28 ` Jesper Dangaard Brouer
2020-02-19 18:38 ` Andrii Nakryiko
2020-02-19 20:06 ` Jesper Dangaard Brouer [this message]
2020-02-19 21:59 ` Daniel Díaz
2020-02-19 22:26 ` Andrii Nakryiko
2020-02-20 0:27 ` Alexei Starovoitov
2020-02-20 0:47 ` shuah
2020-02-20 16:37 ` Jesper Dangaard Brouer
2020-02-20 17:02 ` Bird, Tim
2020-02-20 17:26 ` Alexei Starovoitov
2020-02-20 17:41 ` Bird, Tim
2020-02-20 19:18 ` Alexei Starovoitov
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