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

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 10.03.20 07:08, Michael S. Tsirkin wrote:
> On Mon, Mar 09, 2020 at 07:19:51PM -0700, Alexander Duyck wrote:
>> 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
> 
> 
> I agree. And when we change virtio we likely won't remember to fix up RISC-V.
> So please don't poke at it from arches.
> The right way to do this IMHO is via ARCH_DEFCONFIG, and using
> a defconfig per board.
> And I think the same applies to s390 and virtio console.
> Christian?

Right. The select of VIRTIO_CONSOLE in S390_GUEST ĺooks more like a historic relic.
Will fix.