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Date:   Thu, 13 Sep 2018 15:32:40 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Jakub Kicinski <jakub.kicinski@netronome.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Thomas Richter <tmricht@linux.ibm.com>,
        Hendrik Brueckner <brueckner@linux.ibm.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Networking Development Mailing List 
        <netdev@vger.kernel.org>
Subject: [RFC/fix] Re: libbpf build broken on musl libc (Alpine Linux)
Message-ID: <20180913183240.GF30969@kernel.org>
References: <20180910172903.GB15516@kernel.org>
 <20180911122218.0d2eb3f9@cakuba>
 <20180911121543.GB22689@kernel.org>
 <20180911212451.hvnyfwyvcs4yojqy@ast-mbp>
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Em Tue, Sep 11, 2018 at 02:24:53PM -0700, Alexei Starovoitov escreveu:
> On Tue, Sep 11, 2018 at 09:15:43AM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Sep 11, 2018 at 12:22:18PM +0200, Jakub Kicinski escreveu:
> > > On Mon, 10 Sep 2018 14:29:03 -0300, Arnaldo Carvalho de Melo wrote:
> > > > After lunch I'll work on a patch to fix this, 
> > > Any luck?

> > Well, we need to apply the patch below and make tools/lib/str_error_r.c
> > live in a library that libbpf and perf is linked to.
 
> do you want us to take the patch or you're applying it yourself?

Please do some testing with my perf/libbpf+str_error_r branch, it has
two patches to get this fixed, the one I sent and a prep one making
libbpf link against libapi.

[acme@jouet perf]$ git log --oneline -2
a7ab924b7fec (HEAD -> perf/urgent, acme.korg/perf/libbpf+str_error_r) tools lib bpf: Use str_error_r() to fix the build in Alpine Linux
fb4a79e04c2b tools lib bpf: Build and link to tools/lib/api/
[acme@jouet perf]$

I did a lot of tests to make sure tools/perf, tools/lib/bpf,
tools/bpf/bpftools and the bpf selftests all build as expected, with
OUTPUT= and in place.

The csets have further comments about tricky aspects of this.

- Arnaldo