linux-kernel - Re: [PATCH v2 12/26] modpost: make sym_add_exported() always allocate a new symbol

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Message-ID: <CAKwvOdn7qKKXj61htkJVDOE-ZSx4CcWpqjfquiCSVT1=R0xMGA@mail.gmail.com>
Date:   Tue, 3 May 2022 14:56:47 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        Michal Marek <michal.lkml@...kovi.net>
Subject: Re: [PATCH v2 12/26] modpost: make sym_add_exported() always allocate
 a new symbol

On Sun, May 1, 2022 at 1:42 AM Masahiro Yamada <masahiroy@...nel.org> wrote:
>
> Currently, sym_add_exported() does not allocate a symbol if the same
> name symbol already exists in the hash table.
>
> This does not reflect the real use cases. You can let an external
> module override the in-tree one. In this case, the external module
> will export the same name symbols as the in-tree one. However,
> modpost simply ignores those symbols, then Module.symvers for the
> external module loses its symbols.
>
> sym_add_exported() should allocate a new symbol.
>
> Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>

Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>

> ---
>
> (no changes since v1)
>
>  scripts/mod/modpost.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 1f01fc942f94..c9b75697d0fc 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -412,19 +412,17 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod,
>  {
>         struct symbol *s = find_symbol(name);
>
> -       if (!s) {
> -               s = new_symbol(name, mod, export);
> -               list_add_tail(&s->list, &mod->exported_symbols);
> -       } else if (!external_module || s->module->is_vmlinux ||
> -                  s->module == mod) {
> +       if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
>                 error("%s: '%s' exported twice. Previous export was in %s%s\n",
>                       mod->name, name, s->module->name,
>                       s->module->is_vmlinux ? "" : ".ko");
> -               return s;
>         }
>
> +       s = new_symbol(name, mod, export);
>         s->module = mod;
>         s->export    = export;
> +       list_add_tail(&s->list, &mod->exported_symbols);
> +
>         return s;
>  }
>
> --
> 2.32.0
>


-- 
Thanks,
~Nick Desaulniers