Re: [PATCH v3] kbuild: check uniqueness of module names

[Masahiro Yamada]

Hi Stephen,

On Mon, May 20, 2019 at 8:52 AM Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Hi Masahiro,
>
> On Sat, 18 May 2019 01:07:15 +0900 Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote:
> >
> > It checks not only real modules, but also built-in modules (i.e.
> > controlled by tristate CONFIG option, but currently compiled with =y).
> > Non-unique names for built-in modules also cause problems because
> > /sys/modules/ would fall over.
> >
> > I tested allmodconfig on the latest kernel, and it detected the
> > following:
>
> A powerpc ppc64_defconfig produces:
>
> warning: same basename if the following are built as modules:
>   arch/powerpc/platforms/powermac/nvram.ko
>   drivers/char/nvram.ko
>
> Which is a false positive since
> arch/powerpc/platforms/powermac/Makefile has
>
> # CONFIG_NVRAM is an arch. independent tristate symbol, for pmac32 we really
> # need this to be a bool.  Cheat here and pretend CONFIG_NVRAM=m is really
> # CONFIG_NVRAM=y
> obj-$(CONFIG_NVRAM:m=y)         += nvram.o
>
> Which means that this nvram.o will never be built as a module.

Indeed.

I thought it was a good idea to check built-in modules,
but I do not have a good way to avoid false positives.

I think we should not check modules.builtin.
Anyway, allmodconfig has a good test coverage.

The following is the planned fix.
(I folded your sed code.)




diff --git a/scripts/modules-check.sh b/scripts/modules-check.sh
index 2f659530e1ec..39e8cb36ba19 100755
--- a/scripts/modules-check.sh
+++ b/scripts/modules-check.sh
@@ -6,10 +6,10 @@ set -e
 # Check uniqueness of module names
 check_same_name_modules()
 {
-       for m in $(sed 's:.*/::' modules.order modules.builtin | sort | uniq -d)
+       for m in $(sed 's:.*/::' modules.order | sort | uniq -d)
        do
-               echo "warning: same basename if the following are
built as modules:" >&2
-               sed "/\/$m/!d;s:^kernel/:  :" modules.order modules.builtin >&2
+               echo "warning: same module names found:" >&2
+               sed -n "/\/$m/s:^kernel/:  :p" modules.order >&2
        done
 }






> --
> Cheers,
> Stephen Rothwell



--
Best Regards
Masahiro Yamada