tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y
head:   11bdb6b2eb736558e5a82e1fc665bf434e2304ae
commit: b6f69f72c15d7f973f5709c5351f378f235b3654 [1441/1453] mm: don't rely on system state to detect hot-plug operations
config: powerpc-randconfig-r036-20201008 (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
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/stable/linux-stable-rc.git/commit/?id=b6f69f72c15d7f973f5709c5351f378f235b3654
        git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
        git fetch --no-tags linux-stable-rc linux-4.19.y
        git checkout b6f69f72c15d7f973f5709c5351f378f235b3654
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/base/node.c:429:5: warning: no previous prototype for 'register_mem_block_under_node_early' [-Wmissing-prototypes]
     429 | int register_mem_block_under_node_early(struct memory_block *mem_blk, void *arg)
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

vim +/register_mem_block_under_node_early +429 drivers/base/node.c

   427	
   428	/* register memory section under specified node if it spans that node */
 > 429	int register_mem_block_under_node_early(struct memory_block *mem_blk, void *arg)
   430	{
   431		int nid = *(int *)arg;
   432		unsigned long pfn, sect_start_pfn, sect_end_pfn;
   433	
   434		sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
   435		sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
   436		sect_end_pfn += PAGES_PER_SECTION - 1;
   437		for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
   438			int page_nid;
   439	
   440			/*
   441			 * memory block could have several absent sections from start.
   442			 * skip pfn range from absent section
   443			 */
   444			if (!pfn_present(pfn)) {
   445				pfn = round_down(pfn + PAGES_PER_SECTION,
   446						 PAGES_PER_SECTION) - 1;
   447				continue;
   448			}
   449	
   450			/*
   451			 * We need to check if page belongs to nid only at the boot
   452			 * case because node's ranges can be interleaved.
   453			 */
   454			page_nid = get_nid_for_pfn(pfn);
   455			if (page_nid < 0)
   456				continue;
   457			if (page_nid != nid)
   458				continue;
   459	
   460			return do_register_memory_block_under_node(nid, mem_blk);
   461		}
   462		/* mem section does not span the specified node */
   463		return 0;
   464	}
   465	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org