Hi Daniel, Thank you for the patch! Yet something to improve: [auto build test ERROR on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Xu/Support-direct-writes-to-nf_conn-mark/20220816-060429 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: arm-versatile_defconfig (https://download.01.org/0day-ci/archive/20220819/202208190318.HygywK17-lkp@xxxxxxxxx/config) compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project aed5e3bea138ce581d682158eb61c27b3cfdd6ec) 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 arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://github.com/intel-lab-lkp/linux/commit/c7b21d163eb9c61514dd86baf4281deb4d4387bb git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Daniel-Xu/Support-direct-writes-to-nf_conn-mark/20220816-060429 git checkout c7b21d163eb9c61514dd86baf4281deb4d4387bb # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): >> net/core/filter.c:8723:10: error: call to undeclared function 'btf_struct_access'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, ^ net/core/filter.c:8797:10: error: call to undeclared function 'btf_struct_access'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, ^ 2 errors generated. vim +/btf_struct_access +8723 net/core/filter.c 8714 8715 static int tc_cls_act_btf_struct_access(struct bpf_verifier_log *log, 8716 const struct btf *btf, 8717 const struct btf_type *t, int off, 8718 int size, enum bpf_access_type atype, 8719 u32 *next_btf_id, 8720 enum bpf_type_flag *flag) 8721 { 8722 if (atype == BPF_READ) > 8723 return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, 8724 flag); 8725 8726 return nf_conntrack_btf_struct_access(log, btf, t, off, size, atype, 8727 next_btf_id, flag); 8728 } 8729 -- 0-DAY CI Kernel Test Service https://01.org/lkp