Re: [linux-next:master 7003/7050] include/linux/virtio_config.h:113: undefined reference to `page_reporting_unregister'

[Alexander Duyck <alexander.duyck@gmail.com>]

On Sun, Mar 8, 2020 at 7:54 PM kbuild test robot <lkp@intel.com> wrote:
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   b86a6a241b7c60ca7a6ca4fb3c0d2aedbbf2c1b6
> commit: 120359931943d2b801ce51a1a045dcc0a5d1a55b [7003/7050] Merge branch 'akpm-current/current'
> config: riscv-randconfig-a001-20200308 (attached as .config)
> compiler: riscv64-linux-gcc (GCC) 7.5.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         git checkout 120359931943d2b801ce51a1a045dcc0a5d1a55b
>         # save the attached .config to linux build tree
>         GCC_VERSION=7.5.0 make.cross ARCH=riscv
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
>    drivers/virtio/virtio_balloon.o: In function `leak_balloon':
>    drivers/virtio/virtio_balloon.c:281: undefined reference to `balloon_page_dequeue'
>    drivers/virtio/virtio_balloon.o: In function `__virtio_test_bit':
> >> include/linux/virtio_config.h:113: undefined reference to `page_reporting_unregister'
>    drivers/virtio/virtio_balloon.o: In function `virtio_cread32':
>    include/linux/virtio_config.h:423: undefined reference to `balloon_page_alloc'
>    drivers/virtio/virtio_balloon.o: In function `fill_balloon':
> >> drivers/virtio/virtio_balloon.c:233: undefined reference to `balloon_page_enqueue'
>    drivers/virtio/virtio_balloon.o: In function `__virtio_test_bit':
> >> include/linux/virtio_config.h:113: undefined reference to `page_reporting_register'
>    drivers/gpu/drm/virtio/virtgpu_drv.o: In function `virtio_gpu_remove':
>    drivers/gpu/drm/virtio/virtgpu_drv.c:139: undefined reference to `drm_dev_unplug'
>    drivers/gpu/drm/virtio/virtgpu_drv.c:140: undefined reference to `drm_atomic_helper_shutdown'
>    drivers/gpu/drm/virtio/virtgpu_drv.c:141: undefined reference to `drm_dev_put'
>    drivers/gpu/drm/virtio/virtgpu_drv.o: In function `virtio_gpu_probe':

It looks like somehow the config has CONFIG_VIRTIO_BALLOON enabled,
but didn't select CONFIG_MEMORY_BALLOON nor CONFIG_PAGE_REPORTING That
shouldn't be possible since in drivers/virtio/Kconfig we have the
following:
config VIRTIO_BALLOON
        tristate "Virtio balloon driver"
        depends on VIRTIO
        select MEMORY_BALLOON
        select PAGE_REPORTING

I think I traced the problem down. It looks like it is related to this patch:
    RISC-V: Add kconfig option for QEMU virt machine

    We add kconfig option for QEMU virt machine and select all
    required VIRTIO drivers using this kconfig option.

    Signed-off-by: Anup Patel <anup.patel@wdc.com>
    Reviewed-by: Atish Patra <atish.patra@wdc.com>
    Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
    Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
    Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>


The problem is it is using select to enable things that have
dependencies, and as a result it is enabling things without enabling
the bits needed to support them. That isn't recommended and is
actually called out to something to avoid in the kconfig-language
documentation:
https://elixir.bootlin.com/linux/latest/source/Documentation/kbuild/kconfig-language.rst#L143