linux-kernel - Re: [PATCH v4 10/14] kbuild: check static EXPORT

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Date:   Mon, 9 May 2022 11:05:38 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        Nathan Chancellor <nathan@...nel.org>,
        Nicolas Schier <nicolas@...sle.eu>,
        Peter Zijlstra <peterz@...radead.org>,
        linux-modules@...r.kernel.org, linux-s390@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, clang-built-linux@...glegroups.com,
        Ard Biesheuvel <ardb@...nel.org>,
        Sami Tolvanen <samitolvanen@...gle.com>
Subject: Re: [PATCH v4 10/14] kbuild: check static EXPORT_SYMBOL* by script
 instead of modpost

On Sun, May 8, 2022 at 12:10 PM Masahiro Yamada <masahiroy@...nel.org> wrote:
>
> diff --git a/scripts/check-local-export b/scripts/check-local-export
> new file mode 100755
> index 000000000000..d1721fa63057
> --- /dev/null
> +++ b/scripts/check-local-export
> @@ -0,0 +1,48 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-2.0-only
> +#
> +# Copyright (C) 2022 Masahiro Yamada
> +
> +set -e
> +set -o pipefail
> +
> +declare -A symbol_types
> +declare -a export_symbols
> +
> +exit_code=0
> +
> +while read value type name
> +do
> +       # to avoid error for clang LTO; $name may be empty
> +       if [[ $value = -* && -z $name ]]; then
> +               continue
> +       fi
> +
> +       # The first field (value) may be empty. If so, fix it up.
> +       if [[ -z $name ]]; then
> +          name=${type}
> +          type=${value}
> +       fi

Consider adding examples of output from NM as comments where you're
handling special cases.

Aren't BOTH from LTO?  The first case is:

---------------- T strncpy

while the second is

                 U strncpy

IIUC?

Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>
-- 
Thanks,
~Nick Desaulniers