Hi Florent, I love your patch! Yet something to improve: [auto build test ERROR on bpf/master] url: https://github.com/0day-ci/linux/commits/Florent-Revest/bpf-Fix-nested-bp... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master config: s390-randconfig-r013-20210510 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project a0fed635fe1701470062495a6ffee1c608f3f1bc) 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 s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://github.com/0day-ci/linux/commit/1f5d45d9243d8ca8ece81e778579fc46a... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Florent-Revest/bpf-Fix-nested-bpf_bprintf_prepare-with-more-per-cpu-buffers/20210511-053835 git checkout 1f5d45d9243d8ca8ece81e778579fc46a1946887 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=s390 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 >>): include/linux/percpu-defs.h:252:27: note: expanded from macro 'this_cpu_ptr' #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr) ^~~~~~~~~~~~~~~~ include/linux/percpu-defs.h:241:2: note: expanded from macro 'raw_cpu_ptr' __verify_pcpu_ptr(ptr); \ ^~~~~~~~~~~~~~~~~~~~~~ include/linux/percpu-defs.h:219:52: note: expanded from macro '__verify_pcpu_ptr' const void __percpu *__vpp_verify = (typeof((ptr) + 0))NULL; \ ~~~~~ ^ kernel/bpf/helpers.c:703:30: note: forward declaration of 'struct bpf_bprintf_bufs' static DEFINE_PER_CPU(struct bpf_bprintf_bufs, bpf_bprintf_bufs); ^ kernel/bpf/helpers.c:718:23: error: use of undeclared identifier 'bpf_bprintf_buf'; did you mean 'bpf_bprintf_bufs'? bufs = this_cpu_ptr(&bpf_bprintf_buf); ^~~~~~~~~~~~~~~ bpf_bprintf_bufs include/linux/percpu-defs.h:252:39: note: expanded from macro 'this_cpu_ptr' #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr) ^ include/linux/percpu-defs.h:242:19: note: expanded from macro 'raw_cpu_ptr' arch_raw_cpu_ptr(ptr); \ ^ include/asm-generic/percpu.h:44:48: note: expanded from macro 'arch_raw_cpu_ptr' #define arch_raw_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset) ^ include/linux/percpu-defs.h:231:23: note: expanded from macro 'SHIFT_PERCPU_PTR' RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) ^ include/linux/compiler.h:181:31: note: expanded from macro 'RELOC_HIDE' __ptr = (unsigned long) (ptr); \ ^ kernel/bpf/helpers.c:703:48: note: 'bpf_bprintf_bufs' declared here static DEFINE_PER_CPU(struct bpf_bprintf_bufs, bpf_bprintf_bufs); ^ kernel/bpf/helpers.c:718:23: error: use of undeclared identifier 'bpf_bprintf_buf'; did you mean 'bpf_bprintf_bufs'? bufs = this_cpu_ptr(&bpf_bprintf_buf); ^~~~~~~~~~~~~~~ bpf_bprintf_bufs include/linux/percpu-defs.h:252:39: note: expanded from macro 'this_cpu_ptr' #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr) ^ include/linux/percpu-defs.h:242:19: note: expanded from macro 'raw_cpu_ptr' arch_raw_cpu_ptr(ptr); \ ^ include/asm-generic/percpu.h:44:48: note: expanded from macro 'arch_raw_cpu_ptr' #define arch_raw_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset) ^ include/linux/percpu-defs.h:231:49: note: expanded from macro 'SHIFT_PERCPU_PTR' RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) ^ include/linux/compiler.h:181:31: note: expanded from macro 'RELOC_HIDE' __ptr = (unsigned long) (ptr); \ ^ kernel/bpf/helpers.c:703:48: note: 'bpf_bprintf_bufs' declared here static DEFINE_PER_CPU(struct bpf_bprintf_bufs, bpf_bprintf_bufs); ^ kernel/bpf/helpers.c:718:23: error: use of undeclared identifier 'bpf_bprintf_buf'; did you mean 'bpf_bprintf_bufs'? bufs = this_cpu_ptr(&bpf_bprintf_buf); ^~~~~~~~~~~~~~~ bpf_bprintf_bufs include/linux/percpu-defs.h:252:39: note: expanded from macro 'this_cpu_ptr' #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr) ^ include/linux/percpu-defs.h:242:19: note: expanded from macro 'raw_cpu_ptr' arch_raw_cpu_ptr(ptr); \ ^ include/asm-generic/percpu.h:44:48: note: expanded from macro 'arch_raw_cpu_ptr' #define arch_raw_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset) ^ include/linux/percpu-defs.h:231:23: note: expanded from macro 'SHIFT_PERCPU_PTR' RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) ^ include/linux/compiler.h:182:13: note: expanded from macro 'RELOC_HIDE' (typeof(ptr)) (__ptr + (off)); }) ^ kernel/bpf/helpers.c:703:48: note: 'bpf_bprintf_bufs' declared here static DEFINE_PER_CPU(struct bpf_bprintf_bufs, bpf_bprintf_bufs); ^ kernel/bpf/helpers.c:718:23: error: use of undeclared identifier 'bpf_bprintf_buf'; did you mean 'bpf_bprintf_bufs'? bufs = this_cpu_ptr(&bpf_bprintf_buf); ^~~~~~~~~~~~~~~ bpf_bprintf_bufs include/linux/percpu-defs.h:252:39: note: expanded from macro 'this_cpu_ptr' #define this_cpu_ptr(ptr) raw_cpu_ptr(ptr) ^ include/linux/percpu-defs.h:242:19: note: expanded from macro 'raw_cpu_ptr' arch_raw_cpu_ptr(ptr); \ ^ include/asm-generic/percpu.h:44:48: note: expanded from macro 'arch_raw_cpu_ptr' #define arch_raw_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset) ^ include/linux/percpu-defs.h:231:49: note: expanded from macro 'SHIFT_PERCPU_PTR' RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) ^ include/linux/compiler.h:182:13: note: expanded from macro 'RELOC_HIDE' (typeof(ptr)) (__ptr + (off)); }) ^ kernel/bpf/helpers.c:703:48: note: 'bpf_bprintf_bufs' declared here static DEFINE_PER_CPU(struct bpf_bprintf_bufs, bpf_bprintf_bufs); ^ bufs = this_cpu_ptr(&bpf_bprintf_buf); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/bpf/helpers.c:703:48: error: tentative definition has type 'typeof(struct bpf_bprintf_bufs)' (aka 'struct bpf_bprintf_bufs') that is never completed static DEFINE_PER_CPU(struct bpf_bprintf_bufs, bpf_bprintf_bufs); ^ kernel/bpf/helpers.c:703:30: note: forward declaration of 'struct bpf_bprintf_bufs' static DEFINE_PER_CPU(struct bpf_bprintf_bufs, bpf_bprintf_bufs); ^ 12 warnings and 8 errors generated. vim +718 kernel/bpf/helpers.c 705 706 static int try_get_fmt_tmp_buf(char **tmp_buf) 707 { 708 struct bpf_bprintf_buffers *bufs; 709 int nest_level; 710 711 preempt_disable(); 712 nest_level = this_cpu_inc_return(bpf_bprintf_nest_level); 713 if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) { 714 this_cpu_dec(bpf_bprintf_nest_level); 715 preempt_enable(); 716 return -EBUSY; 717 } 719 *tmp_buf = bufs->tmp_bufs[nest_level - 1]; 720 721 return 0; 722 } 723 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org