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

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Mar 10, 2020 at 02:13:19PM +0530, Anup Patel wrote:
> On Tue, Mar 10, 2020 at 11:38 AM Michael S. Tsirkin <mst@redhat.com> 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.
> 
> I will fix RISC-V Kconfig.
> 
> Is it fine to use "imply" inplace of "select" ?
> 
> Regards,
> Anup

IIUC imply has exactly the same limitations as select,
so this won't do any good.

> > 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?
> >
> > --
> > MST
> >
> >