Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20221129134217.52767-1-changbin.du@gmail.com> <20221129134217.52767-2-changbin.du@gmail.com>
In-Reply-To: <20221129134217.52767-2-changbin.du@gmail.com>
From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Wed, 30 Nov 2022 16:55:13 -0800
Message-ID: <CAEf4BzZ=+DVkNT+Ti2L_ZyqrxwajfN04ou9XDrju704O6Ake4Q@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] libbpf: show error info about missing ".BTF" section
To:     Changbin Du <changbin.du@gmail.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Quentin Monnet <quentin@isovalent.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Shuah Khan <shuah@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        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>,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Mykola Lysenko <mykolal@fb.com>,
        linux-perf-users@vger.kernel.org, linux-kselftest@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Nov 29, 2022 at 5:42 AM Changbin Du <changbin.du@gmail.com> wrote:
>
> Show the real problem instead of just saying "No such file or directory".
>
> Now will print below info:
> libbpf: can not find '.BTF' section
> Error: failed to load BTF from /home/changbin/work/linux/vmlinux: No such file or directory
>
> Signed-off-by: Changbin Du <changbin.du@gmail.com>
> ---
>  tools/lib/bpf/btf.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index d88647da2c7f..1adc0f6019a0 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -990,6 +990,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
>         err = 0;
>
>         if (!btf_data) {
> +               pr_warn("can not find '%s' section\n", BTF_ELF_SEC);

let's use consistent form of error messages:

pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path);

>                 err = -ENOENT;
>                 goto done;
>         }
> --
> 2.37.2
>