linux-kernel - Re: [PATCH 4/4] modpost: do not set ->preloaded for symbols from Module.symvers

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Date:   Thu, 31 Oct 2019 12:51:45 -0400
From:   Jeff Moyer <jmoyer@...hat.com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     linux-kbuild@...r.kernel.org, Sam Ravnborg <sam@...nborg.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        linux-kernel@...r.kernel.org, dan.j.williams@...el.com,
        linux-nvdimm@...ts.01.org
Subject: Re: [PATCH 4/4] modpost: do not set ->preloaded for symbols from Module.symvers

Masahiro Yamada <yamada.masahiro@...ionext.com> writes:

> Now that there is no overwrap between symbols from ELF files and
> ones from Module.symvers.
>
> So, the 'exported twice' warning should be reported irrespective
> of where the symbol in question came from. Only the exceptional case
> is when __crc_<sym> symbol appears before __ksymtab_<sym>. This
> typically occurs for EXPORT_SYMBOL in .S files.

Hi, Masahiro,

After apply this patch, I get the following modpost warnings when doing:

$ make M=tools/tesing/nvdimm
...
  Building modules, stage 2.
  MODPOST 12 modules
WARNING: tools/testing/nvdimm/libnvdimm: 'nvdimm_bus_lock' exported twice. Previous export was in drivers/nvdimm/libnvdimm.ko
WARNING: tools/testing/nvdimm/libnvdimm: 'nvdimm_bus_unlock' exported twice. Previous export was in drivers/nvdimm/libnvdimm.ko
WARNING: tools/testing/nvdimm/libnvdimm: 'is_nvdimm_bus_locked' exported twice. Previous export was in drivers/nvdimm/libnvdimm.ko
WARNING: tools/testing/nvdimm/libnvdimm: 'devm_nvdimm_memremap' exported twice. Previous export was in drivers/nvdimm/libnvdimm.ko
WARNING: tools/testing/nvdimm/libnvdimm: 'nd_fletcher64' exported twice. Previous export was in drivers/nvdimm/libnvdimm.ko
WARNING: tools/testing/nvdimm/libnvdimm: 'to_nd_desc' exported twice. Previous export was in drivers/nvdimm/libnvdimm.ko
WARNING: tools/testing/nvdimm/libnvdimm: 'to_nvdimm_bus_dev' exported twice. Previous export was in drivers/nvdimm/libnvdimm.ko
...

There are a lot of these warnings.  :)  If I revert this patch, no
complaints.

Cheers,
Jeff

>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
> ---
>
>  scripts/mod/modpost.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 5234555cf550..6ca38d10efc5 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -2457,7 +2457,6 @@ static void read_dump(const char *fname, unsigned int kernel)
>  		s = sym_add_exported(symname, namespace, mod,
>  				     export_no(export));
>  		s->kernel    = kernel;
> -		s->preloaded = 1;
>  		s->is_static = 0;
>  		sym_update_crc(symname, mod, crc, export_no(export));
>  	}