tree: https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git bpf/ftrace head: f6ca0faab8697bc6a3a6e4ffcb72b8a0a0a66558 commit: e201e5e6b442644c28e6c9a001ef2b7e4428aa51 [2/6] bpf: Add bpf ftrace link config: arm-aspeed_g4_defconfig (attached as .config) compiler: arm-linux-gnueabi-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/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 e201e5e6b442644c28e6c9a001ef2b7e4428aa51 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): arm-linux-gnueabi-ld: kernel/bpf/syscall.o: in function `bpf_ftrace_function_call': syscall.c:(.text+0xbd8): undefined reference to `__bpf_prog_enter' --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org