tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 3a00d3dfd4b68b208ecd5405e676d06c8ad6bb63 commit: c36f93c29a94b01da6c400033a0cf6ec2d394579 [2796/2998] mm/memory_hotplug: introduce default phys_to_target_node() implementation config: x86_64-randconfig-a011-20200825 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 77e5a195f818b9ace91f7b12ab948b21d7918238) 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 # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout c36f93c29a94b01da6c400033a0cf6ec2d394579 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): >> drivers/nvdimm/e820.c:24:12: error: implicit declaration of function 'phys_to_target_node' [-Werror,-Wimplicit-function-declaration] int nid = phys_to_target_node(res->start); ^ 1 error generated. # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=c36f93c29a94b01da6c400033a0cf6ec2d394579 git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout c36f93c29a94b01da6c400033a0cf6ec2d394579 vim +/phys_to_target_node +24 drivers/nvdimm/e820.c 7a67832c7e44c2 Dan Williams 2015-08-19 19 d76401ade0bb6a Dan Williams 2018-06-02 20 static int e820_register_one(struct resource *res, void *data) d76401ade0bb6a Dan Williams 2018-06-02 21 { d76401ade0bb6a Dan Williams 2018-06-02 22 struct nd_region_desc ndr_desc; d76401ade0bb6a Dan Williams 2018-06-02 23 struct nvdimm_bus *nvdimm_bus = data; 7b27a8622f8027 Dan Williams 2020-02-16 @24 int nid = phys_to_target_node(res->start); d76401ade0bb6a Dan Williams 2018-06-02 25 d76401ade0bb6a Dan Williams 2018-06-02 26 memset(&ndr_desc, 0, sizeof(ndr_desc)); d76401ade0bb6a Dan Williams 2018-06-02 27 ndr_desc.res = res; 7b27a8622f8027 Dan Williams 2020-02-16 28 ndr_desc.numa_node = numa_map_to_online_node(nid); 7b27a8622f8027 Dan Williams 2020-02-16 29 ndr_desc.target_node = nid; d76401ade0bb6a Dan Williams 2018-06-02 30 set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags); d76401ade0bb6a Dan Williams 2018-06-02 31 if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc)) d76401ade0bb6a Dan Williams 2018-06-02 32 return -ENXIO; d76401ade0bb6a Dan Williams 2018-06-02 33 return 0; d76401ade0bb6a Dan Williams 2018-06-02 34 } d76401ade0bb6a Dan Williams 2018-06-02 35 :::::: The code at line 24 was first introduced by commit :::::: 7b27a8622f802761d5c6abd6c37b22312a35343c libnvdimm/e820: Retrieve and populate correct 'target_node' info :::::: TO: Dan Williams :::::: CC: Dan Williams --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org