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Message-ID: <acfff73b4a0b6d325f749b580ee593ce8d0187f6.camel@gmail.com>
Subject: Re: [PATCH v2] libbpf: add pr_warn() for EINVAL cases in
 linker_sanity_check_elf
From:   Eduard Zingerman <eddyz87@gmail.com>
To:     Sergei Trofimovich <slyich@gmail.com>, bpf@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>,
        Yonghong Song <yonghong.song@linux.dev>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>
Date:   Sat, 09 Dec 2023 00:00:32 +0200
In-Reply-To: <20231208215100.435876-1-slyich@gmail.com>
References: <159e94e7ce82e9432bd2bba0141c8feab0a9a2e6.camel@gmail.com>
         <20231208215100.435876-1-slyich@gmail.com>
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On Fri, 2023-12-08 at 21:51 +0000, Sergei Trofimovich wrote:
> Before the change on `i686-linux` `systemd` build failed as:
>=20
>     $ bpftool gen object src/core/bpf/socket_bind/socket-bind.bpf.o src/c=
ore/bpf/socket_bind/socket-bind.bpf.unstripped.o
>     Error: failed to link 'src/core/bpf/socket_bind/socket-bind.bpf.unstr=
ipped.o': Invalid argument (22)
>=20
> After the change it fails as:
>=20
>     $ bpftool gen object src/core/bpf/socket_bind/socket-bind.bpf.o src/c=
ore/bpf/socket_bind/socket-bind.bpf.unstripped.o
>     libbpf: ELF section #9 has inconsistent alignment addr=3D8 !=3D d=3D4=
 in src/core/bpf/socket_bind/socket-bind.bpf.unstripped.o
>     Error: failed to link 'src/core/bpf/socket_bind/socket-bind.bpf.unstr=
ipped.o': Invalid argument (22)
>=20
> Now it's slightly easier to figure out what is wrong with an ELF file.
>=20
> CC: Alexei Starovoitov <ast@kernel.org>
> CC: Daniel Borkmann <daniel@iogearbox.net>
> CC: Andrii Nakryiko <andrii@kernel.org>
> CC: Martin KaFai Lau <martin.lau@linux.dev>
> CC: Song Liu <song@kernel.org>
> CC: Yonghong Song <yonghong.song@linux.dev>
> CC: John Fastabend <john.fastabend@gmail.com>
> CC: KP Singh <kpsingh@kernel.org>
> CC: Stanislav Fomichev <sdf@google.com>
> CC: Hao Luo <haoluo@google.com>
> CC: Jiri Olsa <jolsa@kernel.org>
> CC: Eduard Zingerman <eddyz87@gmail.com>
> CC: bpf@vger.kernel.org
> Signed-off-by: Sergei Trofimovich <slyich@gmail.com>
> ---
>  tools/lib/bpf/linker.c | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
> Change since v1:
> Following Eduard's suggestion added one extra pr_warn() call around
> section alignment and added compared values into warning messages.

Thank you for doing adjustments.
(Note: when I apply this patch locally full CC block is a part of the
       commit message, this is usually omitted from commit messages).

Acked-by: Eduard Zingerman <eddyz87@gmail.com>