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References: <20210814234102.2315551-1-masahiroy@kernel.org> <r3rr2q2-1o70-o012-4ns1-or1qrs665753@syhkavp.arg>
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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Wed, 18 Aug 2021 13:28:49 +0900
Message-ID: <CAK7LNATbyotYzVDc3b8jPk7nC1dLXjc3oMeytwA5WqzsMBPjgA@mail.gmail.com>
Subject: Re: [PATCH] kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
To:     Nicolas Pitre <nico@fluxnic.net>
Cc:     Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        clang-built-linux <clang-built-linux@googlegroups.com>
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On Sun, Aug 15, 2021 at 12:37 PM Nicolas Pitre <nico@fluxnic.net> wrote:
>
> On Sun, 15 Aug 2021, Masahiro Yamada wrote:
>
> > When CONFIG_TRIM_UNUSED_KSYMS is enabled, I see some warnings like this:
> >
> >   nm: arch/x86/entry/vdso/vdso32/note.o: no symbols
> >
> > $NM (both GNU nm and llvm-nm) warns when no symbol is found in the
> > object. Suppress the stderr.
> >
> > Fixes: bbda5ec671d3 ("kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS")
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> > ---
> >
> >  scripts/gen_ksymdeps.sh | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/scripts/gen_ksymdeps.sh b/scripts/gen_ksymdeps.sh
> > index 1324986e1362..5493124e8ee6 100755
> > --- a/scripts/gen_ksymdeps.sh
> > +++ b/scripts/gen_ksymdeps.sh
> > @@ -4,7 +4,10 @@
> >  set -e
> >
> >  # List of exported symbols
> > -ksyms=$($NM $1 | sed -n 's/.*__ksym_marker_\(.*\)/\1/p' | tr A-Z a-z)
> > +#
> > +# If the object has no symbol, $NM warns 'no symbols'.
> > +# Suppress the stdout.
> > +ksyms=$($NM $1 2>/dev/null | sed -n 's/.*__ksym_marker_\(.*\)/\1/p' | tr A-Z a-z)
>
> You mean stderr.


My bad - I will fix it in v2.
Thanks.


-- 
Best Regards
Masahiro Yamada