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From:   Song Liu <song@kernel.org>
Date:   Fri, 15 Apr 2022 16:44:21 -0700
Message-ID: <CAPhsuW6SJ=Gyh89tmJEtsnPqgsE3csDAmkzFky5=yCRuO1JVTQ@mail.gmail.com>
Subject: Re: [PATCH bpf-next 05/11] samples: bpf: use host bpftool to generate
 vmlinux.h, not target
To:     Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc:     Alexander Lobakin <alobakin@pm.me>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@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@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>,
        Magnus Karlsson <magnus.karlsson@intel.com>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Dmitrii Dolgov <9erthalion6@gmail.com>,
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        Willem de Bruijn <willemb@google.com>,
        Daniel Wagner <daniel.wagner@bmw-carit.de>,
        Thomas Graf <tgraf@suug.ch>,
        Ong Boon Leong <boon.leong.ong@intel.com>,
        linux-perf-users@vger.kernel.org,
        open list <linux-kernel@vger.kernel.org>,
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On Fri, Apr 15, 2022 at 6:38 AM Kumar Kartikeya Dwivedi
<memxor@gmail.com> wrote:
>
> On Fri, Apr 15, 2022 at 04:15:50AM IST, Alexander Lobakin wrote:
> > Use the host build of bpftool (bootstrap) instead of the target one
> > to generate vmlinux.h/skeletons for the BPF samples. Otherwise, when
> > host != target, samples compilation fails with:
> >
> > /bin/sh: line 1: samples/bpf/bpftool/bpftool: failed to exec: Exec
> > format error
> >
> > Fixes: 384b6b3bbf0d ("samples: bpf: Add vmlinux.h generation support")
> > Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> > ---
>
> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

Acked-by: Song Liu <songliubraving@fb.com>

>
> >  samples/bpf/Makefile | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> > index 97203c0de252..02f999a8ef84 100644
> > --- a/samples/bpf/Makefile
> > +++ b/samples/bpf/Makefile
> > @@ -291,12 +291,13 @@ $(LIBBPF): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OU
> >
> >  BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool
> >  BPFTOOL_OUTPUT := $(abspath $(BPF_SAMPLES_PATH))/bpftool
> > -BPFTOOL := $(BPFTOOL_OUTPUT)/bpftool
> > +BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool
> >  $(BPFTOOL): $(LIBBPF) $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT)
> >           $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../ \
> >               OUTPUT=$(BPFTOOL_OUTPUT)/ \
> >               LIBBPF_OUTPUT=$(LIBBPF_OUTPUT)/ \
> > -             LIBBPF_DESTDIR=$(LIBBPF_DESTDIR)/
> > +             LIBBPF_DESTDIR=$(LIBBPF_DESTDIR)/ \
> > +             bootstrap
> >
> >  $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
> >       $(call msg,MKDIR,$@)
> > --
> > 2.35.2
> >
> >
>
> --
> Kartikeya