Re: powerpc64-linux-ld: drivers/i2c/busses/i2c-pasemi-core.o:undefined reference to `__this_module'

["Sven Peter" <sven@svenpeter.dev>]

On Mon, Dec 6, 2021, at 11:10, kernel test robot wrote:
> tree:   
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
> master
> head:   0fcfb00b28c0b7884635dacf38e46d60bf3d4eb1
> commit: d88ae2932df0e670610cb741fec442ad12466c03 i2c: pasemi: Add Apple 
> platform driver
> date:   8 weeks ago
> config: powerpc64-randconfig-r023-20211206 
> (https://download.01.org/0day-ci/archive/20211206/202112061809.XT99aPrf-lkp@intel.com/config)
> compiler: powerpc64-linux-gcc (GCC) 11.2.0
> reproduce (this is a W=1 build):
>         wget 
> https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross 
> -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d88ae2932df0e670610cb741fec442ad12466c03
>         git remote add linus 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout d88ae2932df0e670610cb741fec442ad12466c03
>         # save the config file to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross 
> O=build_dir ARCH=powerpc SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All error/warnings (new ones prefixed by >>):
>
>>> powerpc64-linux-ld: warning: orphan section `.stubs' from `drivers/i2c/busses/i2c-pasemi-core.o' being placed in section `.stubs'
>>> powerpc64-linux-ld: drivers/i2c/busses/i2c-pasemi-core.o:(.toc+0x0): undefined reference to `__this_module'

This seems to be triggered by compiling one of {pci,platform} as a module and the
other one as built-in. That setup can only happen with COMPILE_TEST since -pci
is otherwise only compiled for powerpc and -platform for arm64.

-core.c is only built once with THIS_MODULE expanding to __this_module. That will
fail when linking the built-in driver where THIS_MODULE should've been NULL instead.

The most simple fix (that also has no chance of breaking anything) is probably to
just move

  smbus->adapter.owner = THIS_MODULE;

from core to both apple.c and pci.c. I'll prepare a patch later this week.

Sven