Re: [PATCH bpf-next 1/8] bpf: Enable annotating trusted nested pointers

[kernel test robot <lkp@intel.com>]

Hi David,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Vernet/bpf-Enable-annotating-trusted-nested-pointers/20230120-080139
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20230119235833.2948341-2-void%40manifault.com
patch subject: [PATCH bpf-next 1/8] bpf: Enable annotating trusted nested pointers
config: ia64-allyesconfig (https://download.01.org/0day-ci/archive/20230120/202301200957.At49rpzu-lkp@intel.com/config)
compiler: ia64-linux-gcc (GCC) 12.1.0
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://github.com/intel-lab-lkp/linux/commit/8f6df14342b1be3516f8e21037edf771df851427
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review David-Vernet/bpf-Enable-annotating-trusted-nested-pointers/20230120-080139
        git checkout 8f6df14342b1be3516f8e21037edf771df851427
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=ia64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=ia64 SHELL=/bin/bash kernel/bpf/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> kernel/bpf/btf.c:533:5: warning: no previous prototype for 'bpf_find_btf_id' [-Wmissing-prototypes]
     533 | s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
         |     ^~~~~~~~~~~~~~~
   kernel/bpf/btf.c: In function 'btf_seq_show':
   kernel/bpf/btf.c:6977:29: warning: function 'btf_seq_show' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
    6977 |         seq_vprintf((struct seq_file *)show->target, fmt, args);
         |                             ^~~~~~~~
   kernel/bpf/btf.c: In function 'btf_snprintf_show':
   kernel/bpf/btf.c:7014:9: warning: function 'btf_snprintf_show' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
    7014 |         len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
         |         ^~~


vim +/bpf_find_btf_id +533 kernel/bpf/btf.c

   532	
 > 533	s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
   534	{
   535		struct btf *btf;
   536		s32 ret;
   537		int id;
   538	
   539		btf = bpf_get_btf_vmlinux();
   540		if (IS_ERR(btf))
   541			return PTR_ERR(btf);
   542		if (!btf)
   543			return -EINVAL;
   544	
   545		ret = btf_find_by_name_kind(btf, name, kind);
   546		/* ret is never zero, since btf_find_by_name_kind returns
   547		 * positive btf_id or negative error.
   548		 */
   549		if (ret > 0) {
   550			btf_get(btf);
   551			*btf_p = btf;
   552			return ret;
   553		}
   554	
   555		/* If name is not found in vmlinux's BTF then search in module's BTFs */
   556		spin_lock_bh(&btf_idr_lock);
   557		idr_for_each_entry(&btf_idr, btf, id) {
   558			if (!btf_is_module(btf))
   559				continue;
   560			/* linear search could be slow hence unlock/lock
   561			 * the IDR to avoiding holding it for too long
   562			 */
   563			btf_get(btf);
   564			spin_unlock_bh(&btf_idr_lock);
   565			ret = btf_find_by_name_kind(btf, name, kind);
   566			if (ret > 0) {
   567				*btf_p = btf;
   568				return ret;
   569			}
   570			spin_lock_bh(&btf_idr_lock);
   571			btf_put(btf);
   572		}
   573		spin_unlock_bh(&btf_idr_lock);
   574		return ret;
   575	}
   576	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests