linux-kernel - Re: [PATCH] mostpost: don't warn about symbols from another file

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Date:   Sat, 7 Sep 2019 01:39:11 +0300
From:   Denis Efremov <efremov@...ux.com>
To:     Arnd Bergmann <arnd@...db.de>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Michal Marek <michal.lkml@...kovi.net>
Cc:     Emil Velikov <emil.l.velikov@...il.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Sam Ravnborg <sam@...nborg.org>,
        WANG Chao <chao.wang@...oud.cn>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mostpost: don't warn about symbols from another file

Hi,

On 06.09.2019 18:10, Arnd Bergmann wrote:
> On architectures such as ARM that have a list of symbols exported from
> assembler in a separate C file, we get a lot of new warnings:
> 
> WARNING: "__ashrdi3" [vmlinux] is a static (unknown)
> WARNING: "__lshrdi3" [vmlinux] is a static (unknown)
> WARNING: "__aeabi_llsr" [vmlinux] is a static (unknown)
> WARNING: "__aeabi_lasr" [vmlinux] is a static (unknown)
> WARNING: "__aeabi_uidivmod" [vmlinux] is a static (unknown)
> WARNING: "__udivsi3" [vmlinux] is a static (unknown)
> WARNING: "_change_bit" [vmlinux] is a static (unknown)
> WARNING: "__aeabi_idiv" [vmlinux] is a static (unknown)
> WARNING: "__umodsi3" [vmlinux] is a static (unknown)
> WARNING: "__aeabi_uidiv" [vmlinux] is a static (unknown)
> WARNING: "__aeabi_idivmod" [vmlinux] is a static (unknown)
> WARNING: "__muldi3" [vmlinux] is a static (unknown)
> WARNING: "__aeabi_ulcmp" [vmlinux] is a static (unknown)
> WARNING: "__raw_writesb" [vmlinux] is a static (unknown)
> WARNING: "__raw_readsb" [vmlinux] is a static (unknown)
> ...
> 
> This is not helpful, as these are clearly not static symbols
> at all. Suppress the warning in a case like this.
> 

It looks very similar to this discussion https://lkml.org/lkml/2019/7/30/112

Could you please write the steps to reproduce the warnings?
Now, I'm trying to build linux-next (host Ubuntu 19.04 x86_64) with:
$ make ARCH=arm CROSS_COMPILE=/usr/bin/arm-linux-gnueabi-
But I can't get these warnings.

I would like to check the type of this asm symbols. It seems like they
are STT_NOTYPE. In this case the fix could also involve ELF_ST_TYPE check.

Thanks,
Denis

> Fixes: 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  scripts/mod/modpost.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 76c221dd9b2b..4265dd924933 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -2543,7 +2543,7 @@ int main(int argc, char **argv)
>  		struct symbol *s = symbolhash[n];
>  
>  		while (s) {
> -			if (s->is_static)
> +			if (s->is_static && s->export != export_unknown)
>  				warn("\"%s\" [%s] is a static %s\n",
>  				     s->name, s->module->name,
>  				     export_str(s->export));
>