Hi Hangbin, [FYI, it's a private test report for your RFC patch.] [auto build test WARNING on bpf-next/master] [also build test WARNING on bpf/master net/master net-next/master linus/master v5.7-rc1 next-20200415] [cannot apply to ipvs/master] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Hangbin-Liu/xdp-add-dev-map-mult... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: i386-tinyconfig (attached as .config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce: # save the attached .config to linux build tree make ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): In file included from include/linux/bpf-cgroup.h:5:0, from include/linux/cgroup-defs.h:22, from include/linux/cgroup.h:28, from include/linux/memcontrol.h:13, from include/linux/swap.h:9, from include/linux/suspend.h:5, from arch/x86/kernel/asm-offsets.c:13: include/linux/bpf.h: In function 'array_of_map_lookup_elem': } ^ include/linux/bpf.h: In function 'htab_of_map_lookup_elem': include/linux/bpf.h:1293:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ In file included from include/linux/bpf-cgroup.h:5:0, from include/linux/cgroup-defs.h:22, from include/linux/cgroup.h:28, from include/linux/memcontrol.h:13, from include/linux/swap.h:9, from include/linux/suspend.h:5, from arch/x86/kernel/asm-offsets.c:13: At top level: include/linux/bpf.h:1290:14: warning: 'htab_of_map_lookup_elem' defined but not used [-Wunused-function] static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key) ^~~~~~~~~~~~~~~~~~~~~~~ include/linux/bpf.h:1285:14: warning: 'array_of_map_lookup_elem' defined but not used [-Wunused-function] static void *array_of_map_lookup_elem(struct bpf_map *map, void *key) ^~~~~~~~~~~~~~~~~~~~~~~~ -- In file included from include/linux/bpf-cgroup.h:5:0, from include/linux/cgroup-defs.h:22, from include/linux/cgroup.h:28, from include/linux/memcontrol.h:13, from include/linux/swap.h:9, from include/linux/suspend.h:5, from arch/x86/kernel/asm-offsets.c:13: include/linux/bpf.h: In function 'array_of_map_lookup_elem': } ^ include/linux/bpf.h: In function 'htab_of_map_lookup_elem': include/linux/bpf.h:1293:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ In file included from include/linux/bpf-cgroup.h:5:0, from include/linux/cgroup-defs.h:22, from include/linux/cgroup.h:28, from include/linux/memcontrol.h:13, from include/linux/swap.h:9, from include/linux/suspend.h:5, from arch/x86/kernel/asm-offsets.c:13: At top level: include/linux/bpf.h:1290:14: warning: 'htab_of_map_lookup_elem' defined but not used [-Wunused-function] static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key) ^~~~~~~~~~~~~~~~~~~~~~~ include/linux/bpf.h:1285:14: warning: 'array_of_map_lookup_elem' defined but not used [-Wunused-function] static void *array_of_map_lookup_elem(struct bpf_map *map, void *key) ^~~~~~~~~~~~~~~~~~~~~~~~ 22 real 4 user 6 sys 50.68% cpu make prepare vim +1288 include/linux/bpf.h 1287 1289 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org