Hi Masami, [FYI, it's a private test report for your RFC patch.] [auto build test WARNING on rostedt-trace/for-next] [also build test WARNING on bpf-next/master bpf/master linus/master v5.16] [cannot apply to next-20220112] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Masami-Hiramatsu/fprobe-Add-ftra... base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next config: hexagon-randconfig-r001-20220112 (https://download.01.org/0day-ci/archive/20220113/202201130747.yNR0J8tO-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 244dd2913a43a200f5a6544d424cdc37b771028b) 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://github.com/0day-ci/linux/commit/ba002e6556acd9e0af16442f4226ddb2a... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Masami-Hiramatsu/fprobe-Add-ftrace-based-probe-APIs/20220112-000050 git checkout ba002e6556acd9e0af16442f4226ddb2a8759567 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash kernel/bpf/ 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/syscall.c:34: include/linux/fprobes.h:28:20: error: field has incomplete type 'struct ftrace_ops' struct ftrace_ops ftrace; ^ include/linux/ftrace.h:332:8: note: forward declaration of 'struct ftrace_ops' struct ftrace_ops; ^ In file included from kernel/bpf/syscall.c:34: struct fprobe_entry *fprobe_find_entry(struct fprobe *fp, unsigned long addr) ^ include/linux/fprobes.h:57:1: note: declare 'static' if the function is not intended to be used outside of this translation unit struct fprobe_entry *fprobe_find_entry(struct fprobe *fp, unsigned long addr) ^ static 1 warning and 1 error generated. vim +/fprobe_find_entry +57 include/linux/fprobes.h 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 43 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 44 #ifdef CONFIG_FPROBES 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 45 int register_fprobe(struct fprobe *fp); 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 46 int unregister_fprobe(struct fprobe *fp); 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 47 struct fprobe_entry *fprobe_find_entry(struct fprobe *fp, unsigned long addr); 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 48 #else 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 49 static inline int register_fprobe(struct fprobe *fp) 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 50 { 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 51 return -ENOTSUPP; 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 52 } 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 53 static inline int unregister_fprobe(struct fprobe *fp) 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 54 { 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 55 return -ENOTSUPP; 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 56 } 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 @57 struct fprobe_entry *fprobe_find_entry(struct fprobe *fp, unsigned long addr) 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 58 { 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 59 return NULL; 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 60 } 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 61 #endif 7b8ed3653f37559 Masami Hiramatsu 2022-01-12 62 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org