tree: https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git bpf/ftrace head: 75bc48cb4414f68f3a427d021860af113920adfd commit: a1f1f141147a15afbfcc897661c59e23285f941a [3/7] bpf: Add support to attach program to ftrace probe config: powerpc64-randconfig-r016-20210413 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 9829f5e6b1bca9b61efc629770d28bb9014dec45) 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 powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/commit/?id... git remote add jolsa-perf https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git git fetch --no-tags jolsa-perf bpf/ftrace git checkout a1f1f141147a15afbfcc897661c59e23285f941a # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 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 >>): void bpf_ftrace_probe(unsigned long ip __maybe_unused, ^ kernel/bpf/verifier.c:12799:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void bpf_ftrace_probe(unsigned long ip __maybe_unused, ^ static 1 warning generated. vim +/bpf_ftrace_probe +12799 kernel/bpf/verifier.c 12797 12798 __maybe_unused 12799 void bpf_ftrace_probe(unsigned long ip __maybe_unused, 12800 unsigned long parent_ip __maybe_unused) { } 12801 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org