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References: <20230521160426.1881124-1-masahiroy@kernel.org> <20230521160426.1881124-21-masahiroy@kernel.org>
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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Thu, 25 May 2023 11:26:49 -0700
Message-ID: <CAKwvOdmwb3a-YvA4qN6=ed1YeQY_yG0qJnboX23CjCMOH8HmMQ@mail.gmail.com>
Subject: Re: [PATCH v6 20/20] modpost: show offset from symbol for section
 mismatch warnings
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nicolas Schier <nicolas@fjasle.eu>
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On Sun, May 21, 2023 at 9:05=E2=80=AFAM Masahiro Yamada <masahiroy@kernel.o=
rg> wrote:
>
> Currently, modpost only shows the symbol names and section names, so it
> repeats the same message if there are multiple relocations in the same
> symbol. It is common the relocation spans across multiple instructions.
>
> It is better to show the offset from the symbol.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
>
>  scripts/mod/modpost.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index e7561fa57478..4da96746a03b 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -1135,8 +1135,8 @@ static void default_mismatch_handler(const char *mo=
dname, struct elf_info *elf,
>
>         sec_mismatch_count++;
>
> -       warn("%s: section mismatch in reference: %s (section: %s) -> %s (=
section: %s)\n",
> -            modname, fromsym, fromsec, tosym, tosec);
> +       warn("%s: section mismatch in reference: %s+0x%x (section: %s) ->=
 %s (section: %s)\n",
> +            modname, fromsym, (unsigned int)(faddr - from->st_value), fr=
omsec, tosym, tosec);

Is the cast necessary if you use the %p format specifier instead of 0x%x?

>
>         if (mismatch->mismatch =3D=3D EXTABLE_TO_NON_TEXT) {
>                 if (match(tosec, mismatch->bad_tosec))
> --
> 2.39.2
>


--=20
Thanks,
~Nick Desaulniers