Hi Michael,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git balloon
head:   b145636d693114d343a0a47a4400f5b31e211fec
commit: c4af912c65bc897b31264a3403f18b0cf52fa10c [12/38] mm: use folio_zero_user for user pages in post_alloc_hook
config: m68k-allnoconfig (https://download.01.org/0day-ci/archive/20260605/202606051337.Pac8xsTQ-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260605/202606051337.Pac8xsTQ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot [off-list ref]
| Closes: https://lore.kernel.org/oe-kbuild-all/202606051337.Pac8xsTQ-lkp@intel.com/ (local)

All errors (new ones prefixed by >>):

   m68k-linux-ld: mm/page_alloc.o: in function `post_alloc_hook':

quoted

page_alloc.c:(.text+0x3b42): undefined reference to `folio_zero_user'

   m68k-linux-ld: mm/page_alloc.o: in function `get_page_from_freelist':
   page_alloc.c:(.text+0x546a): undefined reference to `folio_zero_user'

quoted

m68k-linux-ld: page_alloc.c:(.text+0x550c): undefined reference to `folio_zero_user'

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki