linux-kernel - Re: [PATCH] kbuild: remove duplicate dependencies from .mod files

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Date:   Wed, 12 Feb 2020 22:22:27 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Sami Tolvanen <samitolvanen@...gle.com>
Cc:     Michal Marek <michal.lkml@...kovi.net>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kbuild: remove duplicate dependencies from .mod files

Hi Sami,

On Mon, Feb 10, 2020 at 10:19 PM Sami Tolvanen <samitolvanen@...gle.com> wrote:
>
> With CONFIG_TRIM_UNUSED_SYMS, if a module has enough dependencies to
> exceed the default xargs command line size limit, the output is split
> into multiple lines, which can result in used symbols getting trimmed.
>
> This change removes duplicate dependencies, which will reduce the
> probability of this happening and makes .mod files smaller and easier
> to read.
>
> Signed-off-by: Sami Tolvanen <samitolvanen@...gle.com>
> ---
>  scripts/Makefile.build | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index a1730d42e5f3..a083bcec19d3 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -257,7 +257,7 @@ endef
>
>  # List module undefined symbols (or empty line if not enabled)
>  ifdef CONFIG_TRIM_UNUSED_KSYMS
> -cmd_undef_syms = $(NM) $< | sed -n 's/^  *U //p' | xargs echo
> +cmd_undef_syms = $(NM) $< | sed -n 's/^  *U //p' | sort -u | xargs echo



In which case are undefined symbols duplicated?

Do you have a .config to reproduce it?



>  else
>  cmd_undef_syms = echo
>  endif
>
> base-commit: bb6d3fb354c5ee8d6bde2d576eb7220ea09862b9
> --
> 2.25.0.341.g760bfbb309-goog
>


-- 
Best Regards
Masahiro Yamada