Hi Alan, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Alan-Maguire/bpf-add-helpers-to-... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: sparc-randconfig-p002-20200917 (attached as .config) compiler: sparc-linux-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 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sparc 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 >>): 5310 | void btf_type_show(const struct btf *btf, u32 type_id, void *obj, | ^~~~~~~~~~~~~ kernel/bpf/btf.c: In function 'btf_seq_show': 5327 | seq_vprintf((struct seq_file *)show->target, fmt, args); | ^~~~~~~~ kernel/bpf/btf.c: In function 'btf_snprintf_show': 5357 | len = vsnprintf(show->target, ssnprintf->len_left, fmt, args); | ^~~ # https://github.com/0day-ci/linux/commit/a85186d405b24251bfd7179ae1949f345... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Alan-Maguire/bpf-add-helpers-to-support-BTF-based-kernel-data-display/20200918-213932 git checkout a85186d405b24251bfd7179ae1949f3458e9702d vim +/btf_type_show +5310 kernel/bpf/btf.c 5309 5311 struct btf_show *show) 5312 { 5313 const struct btf_type *t = btf_type_by_id(btf, type_id); 5314 5315 show->btf = btf; 5316 memset(&show->state, 0, sizeof(show->state)); 5317 memset(&show->obj, 0, sizeof(show->obj)); 5318 5319 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show); 5320 } 5321 5322 static void btf_seq_show(struct btf_show *show, const char *fmt, ...) 5323 { 5324 va_list args; 5325 5326 va_start(args, fmt); 5328 va_end(args); 5329 } 5330 5331 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, 5332 struct seq_file *m) 5333 { 5334 struct btf_show sseq; 5335 5336 sseq.target = m; 5337 sseq.showfn = btf_seq_show; 5338 sseq.flags = BTF_SHOW_NONAME | BTF_SHOW_COMPACT | BTF_SHOW_ZERO | 5339 BTF_SHOW_UNSAFE; 5340 5341 btf_type_show(btf, type_id, obj, &sseq); 5342 } 5343 5344 struct btf_show_snprintf { 5345 struct btf_show show; 5346 int len_left; /* space left in string */ 5347 int len; /* length we would have written */ 5348 }; 5349 5350 static void btf_snprintf_show(struct btf_show *show, const char *fmt, ...) 5351 { 5352 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show; 5353 va_list args; 5354 int len; 5355 5356 va_start(args, fmt); 5358 va_end(args); 5359 5360 if (len < 0) { 5361 ssnprintf->len_left = 0; 5362 ssnprintf->len = len; 5363 } else if (len > ssnprintf->len_left) { 5364 /* no space, drive on to get length we would have written */ 5365 ssnprintf->len_left = 0; 5366 ssnprintf->len += len; 5367 } else { 5368 ssnprintf->len_left -= len; 5369 ssnprintf->len += len; 5370 show->target += len; 5371 } 5372 } 5373 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org