ERROR: modpost: __mulodi4 [drivers/block/nbd.ko] undefined!

ERROR: modpost: __mulodi4 [drivers/block/nbd.ko] undefined!

[Naresh Kamboju]

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.

Build config:
https://builds.tuxbuild.com/1xqOnCtgaWedE8U8jhmbI3FuAuJ/config

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

meta data:
-----------
    git_describe: next-20210908
    git_ref:
    git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
    git_sha: 999569d59a0aa2509ae4a67ecc266c1134e37e7b
    git_short_log: 999569d59a0a (\Add linux-next specific files for 20210908\)
    kconfig: [
        mini2440_defconfig
    ],
    target_arch: arm
    toolchain: clang-13

steps to reproduce:
https://builds.tuxbuild.com/1xqOnCtgaWedE8U8jhmbI3FuAuJ/tuxmake_reproducer.sh

--
Linaro LKFT
https://lkft.linaro.org

Re: ERROR: modpost: __mulodi4 [drivers/block/nbd.ko] undefined!

[Nathan Chancellor]

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