tree: https://git.kernel.org/pub/scm/linux/kernel/git/toke/linux.git xdp-queueing-01 head: 6b5756c44933d2b55e5e59e1196ef95894203cf7 commit: b8d0d0f924c237daf55b430a85007bd41ad01d7e [1/3] Add a PIFO map type for queueing packets config: powerpc-randconfig-r026-20210709 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 8d69635ed9ecf36fd0ca85906bfde17949671cbe) 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 powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/toke/linux.git/commit/?id... git remote add toke https://git.kernel.org/pub/scm/linux/kernel/git/toke/linux.git git fetch --no-tags toke xdp-queueing-01 git checkout b8d0d0f924c237daf55b430a85007bd41ad01d7e # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): In file included from kernel/bpf/pifomap.c:5: In file included from include/linux/bpf.h:9: In file included from include/linux/workqueue.h:9: In file included from include/linux/timer.h:5: In file included from include/linux/list.h:9: In file included from include/linux/kernel.h:12: In file included from include/linux/bitops.h:32: In file included from arch/powerpc/include/asm/bitops.h:62: arch/powerpc/include/asm/barrier.h:49:9: warning: '__lwsync' macro redefined [-Wmacro-redefined] #define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory") ^ <built-in>:309:9: note: previous definition is here #define __lwsync __builtin_ppc_lwsync ^ if (pktid < pifo->qsize) ^~~~~~~~~~~~~~~~~~~ kernel/bpf/pifomap.c:149:9: note: uninitialized use occurs here return pkt ? &pkt->pkt_id : NULL; ^~~ kernel/bpf/pifomap.c:146:2: note: remove the 'if' if its condition is always true if (pktid < pifo->qsize) ^~~~~~~~~~~~~~~~~~~~~~~~ kernel/bpf/pifomap.c:143:26: note: initialize the variable 'pkt' to silence this warning struct bpf_pifo_pkt *pkt; ^ = NULL 2 warnings generated. vim +146 kernel/bpf/pifomap.c 139 140 static void *pifo_map_lookup_elem(struct bpf_map *map, void *key) 141 { 142 struct bpf_pifo_map *pifo = container_of(map, struct bpf_pifo_map, map); 143 struct bpf_pifo_pkt *pkt; 144 u32 pktid = *(u32 *)key; 145 147 pkt = &pifo->q[pktid]; 148 149 return pkt ? &pkt->pkt_id : NULL; 150 } 151 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org