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Date:   Wed, 8 Sep 2021 09:56:53 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Naresh Kamboju <naresh.kamboju@linaro.org>
Cc:     linux-block <linux-block@vger.kernel.org>, nbd@other.debian.org,
        open list <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Josef Bacik <josef@toxicpanda.com>,
        Jens Axboe <axboe@kernel.dk>, lkft-triage@lists.linaro.org,
        Nick Desaulniers <ndesaulniers@google.com>,
        Arnd Bergmann <arnd@arndb.de>, llvm@lists.linux.dev
Subject: Re: ERROR: modpost: __mulodi4 [drivers/block/nbd.ko] undefined!
Message-ID: <YTjrVWaTIA5ZZumW@archlinux-ax161>
References: <CA+G9fYvThAuTu1-Tg+7BaFofxfBkvBuTAnycuws-U4p473MeZQ@mail.gmail.com>
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Hi Naresh,

On Wed, Sep 08, 2021 at 04:58:11PM +0530, Naresh Kamboju wrote:
> Following build warnings/ errors noticed while building linux next
> master branch with clang-13 for arm architecture with following configs.
>   - footbridge_defconfig
>   - mini2440_defconfig
>   - s3c2410_defconfig
> 
> ERROR: modpost: __mulodi4 [drivers/block/nbd.ko] undefined!
> make[2]: *** [/builds/linux/scripts/Makefile.modpost:134:
> modules-only.symvers] Error 1
> make[2]: *** Deleting file 'modules-only.symvers'
> make[2]: Target '__modpost' not remade because of errors.
> make[1]: *** [/builds/linux/Makefile:1952: modules] Error 2
> make[1]: Target '__all' not remade because of errors.
> make: *** [Makefile:226: __sub-make] Error 2
> make: Target '__all' not remade because of errors.

Thanks for the report. This is a known issue that we have been tracking
and it is now resolved in LLVM 14:

https://github.com/ClangBuiltLinux/linux/issues/1438

Nick said he should have a kernel patch to work around this in the
kernel for older versions of LLVM soon.

By the way, can you use our new mailing list and my kernel.org address
for future reports (llvm@lists.linux.devi, nathan@kernel.org)? It will
make it easier to find these reports in the archives in the future and
my filters will catch this better.

Cheers,
Nathan