On Mon, Dec 6, 2021, at 20:47, Arnd Bergmann wrote: > On Mon, Dec 6, 2021 at 6:02 PM Sven Peter <sven@xxxxxxxxxxxxx> wrote: >> On Mon, Dec 6, 2021, at 11:10, kernel test robot wrote: > >> > If you fix the issue, kindly add following tag as appropriate >> > Reported-by: kernel test robot <lkp@xxxxxxxxx> >> > >> > 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. > > I'd prefer fixing this in a better way, linking an object file into > both vmlinux and a loadable > module is not supported at all. Make sense, I didn't know that. > Other options are: > > - #include the common .c file from the individual drivers (not great) > - use Kconfig logic to prevent the broken configuration > - use Makefile tricks to make both drivers built-in when this happens > - make the common part a separate loadable module, exporting all the > global symbols. > > Out of these, I would prefer the last option. Sure, I'll see when I can spare some time to do that since testing that is going to be a bit more annoying with my current setup. Fwiw, I2C_OCTEON and I2C_THUNDERX might have the same issue as well with i2c-octeon-core.o. It just won't result in the same compile error because i2c-octeon-core.c doesn't use THIS_MODULE. It's also nothing that is likely to ever happen since those two drivers are also never used on the same arch and it should only be possible to create a broken configuration with COMPILE_TEST as well. Sven