Re: [PATCH v2 bpf-next 3/8] bpf: add support for open-coded iterator loops

[kernel test robot <lkp@xxxxxxxxx>]

Hi Andrii,

I love your patch! Perhaps something to improve:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Andrii-Nakryiko/bpf-factor-out-fetching-basic-kfunc-metadata/20230308-055530
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20230307215329.3895377-4-andrii%40kernel.org
patch subject: [PATCH v2 bpf-next 3/8] bpf: add support for open-coded iterator loops
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20230308/202303080733.7uzHxIB0-lkp@xxxxxxxxx/config)
compiler: m68k-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/9eada50b93c4fc3f41032699fda73bc125b37d0e
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Andrii-Nakryiko/bpf-factor-out-fetching-basic-kfunc-metadata/20230308-055530
        git checkout 9eada50b93c4fc3f41032699fda73bc125b37d0e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash kernel/bpf/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Link: https://lore.kernel.org/oe-kbuild-all/202303080733.7uzHxIB0-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

   kernel/bpf/verifier.c: In function 'is_iter_reg_valid_init':
>> kernel/bpf/verifier.c:1255:32: warning: variable 't' set but not used [-Wunused-but-set-variable]
    1255 |         const struct btf_type *t;
         |                                ^


vim +/t +1255 kernel/bpf/verifier.c

  1250	
  1251	static bool is_iter_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
  1252					   struct btf *btf, u32 btf_id, int nr_slots)
  1253	{
  1254		struct bpf_func_state *state = func(env, reg);
> 1255		const struct btf_type *t;
  1256		int spi, i, j;
  1257	
  1258		spi = iter_get_spi(env, reg, nr_slots);
  1259		if (spi < 0)
  1260			return false;
  1261	
  1262		t = btf_type_by_id(btf, btf_id);
  1263	
  1264		for (i = 0; i < nr_slots; i++) {
  1265			struct bpf_stack_state *slot = &state->stack[spi - i];
  1266			struct bpf_reg_state *st = &slot->spilled_ptr;
  1267	
  1268			/* only main (first) slot has ref_obj_id set */
  1269			if (i == 0 && !st->ref_obj_id)
  1270				return false;
  1271			if (i != 0 && st->ref_obj_id)
  1272				return false;
  1273			if (st->iter.btf != btf || st->iter.btf_id != btf_id)
  1274				return false;
  1275	
  1276			for (j = 0; j < BPF_REG_SIZE; j++)
  1277				if (slot->slot_type[j] != STACK_ITER)
  1278					return false;
  1279		}
  1280	
  1281		return true;
  1282	}
  1283	

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