Hi Andrii, kernel test robot noticed the following build warnings: [auto build test WARNING on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Andrii-Nakryiko/bpf-log-PTR_TO_MEM-memory-size-in-verifier-log/20231205-074451 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master patch link: https://lore.kernel.org/r/20231204233931.49758-10-andrii%40kernel.org patch subject: [PATCH bpf-next 09/13] bpf: reuse subprog argument parsing logic for subprog call checks config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20231205/202312051858.R1gH7aIp-lkp@xxxxxxxxx/config) compiler: alpha-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231205/202312051858.R1gH7aIp-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202312051858.R1gH7aIp-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): kernel/bpf/verifier.c:5083:5: warning: no previous prototype for 'check_ptr_off_reg' [-Wmissing-prototypes] 5083 | int check_ptr_off_reg(struct bpf_verifier_env *env, | ^~~~~~~~~~~~~~~~~ kernel/bpf/verifier.c:7268:5: warning: no previous prototype for 'check_mem_reg' [-Wmissing-prototypes] 7268 | int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, | ^~~~~~~~~~~~~ kernel/bpf/verifier.c:8254:5: warning: no previous prototype for 'check_func_arg_reg_off' [-Wmissing-prototypes] 8254 | int check_func_arg_reg_off(struct bpf_verifier_env *env, | ^~~~~~~~~~~~~~~~~~~~~~ kernel/bpf/verifier.c: In function 'btf_check_func_arg_match': >> kernel/bpf/verifier.c:9223:21: warning: variable 'func_name' set but not used [-Wunused-but-set-variable] 9223 | const char *func_name; | ^~~~~~~~~ kernel/bpf/verifier.c: At top level: >> kernel/bpf/verifier.c:9291:5: warning: no previous prototype for 'btf_check_subprog_call' [-Wmissing-prototypes] 9291 | int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog, | ^~~~~~~~~~~~~~~~~~~~~~ vim +/func_name +9223 kernel/bpf/verifier.c 9216 9217 static int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, 9218 const struct btf *btf, u32 func_id, 9219 struct bpf_reg_state *regs) 9220 { 9221 struct bpf_subprog_info *sub = subprog_info(env, subprog); 9222 struct bpf_verifier_log *log = &env->log; > 9223 const char *func_name; 9224 const struct btf_type *fn_t; 9225 u32 i; 9226 int ret; 9227 9228 ret = btf_prepare_func_args(env, subprog); 9229 if (ret) 9230 return ret; 9231 9232 fn_t = btf_type_by_id(btf, func_id); 9233 if (!fn_t || !btf_type_is_func(fn_t)) { 9234 /* These checks were already done by the verifier while loading 9235 * struct bpf_func_info or in add_kfunc_call(). 9236 */ 9237 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n", 9238 func_id); 9239 return -EFAULT; 9240 } 9241 func_name = btf_name_by_offset(btf, fn_t->name_off); 9242 9243 /* check that BTF function arguments match actual types that the 9244 * verifier sees. 9245 */ 9246 for (i = 0; i < sub->arg_cnt; i++) { 9247 u32 regno = i + 1; 9248 struct bpf_reg_state *reg = ®s[regno]; 9249 struct bpf_subprog_arg_info *arg = &sub->args[i]; 9250 9251 if (arg->arg_type == ARG_SCALAR) { 9252 if (reg->type != SCALAR_VALUE) { 9253 bpf_log(log, "R%d is not a scalar\n", regno); 9254 return -EINVAL; 9255 } 9256 } else if (arg->arg_type == ARG_PTR_TO_CTX) { 9257 ret = check_func_arg_reg_off(env, reg, regno, ARG_DONTCARE); 9258 if (ret < 0) 9259 return ret; 9260 /* If function expects ctx type in BTF check that caller 9261 * is passing PTR_TO_CTX. 9262 */ 9263 if (reg->type != PTR_TO_CTX) { 9264 bpf_log(log, "arg#%d expects pointer to ctx\n", i); 9265 return -EINVAL; 9266 } 9267 } else if (base_type(arg->arg_type) == ARG_PTR_TO_MEM) { 9268 ret = check_func_arg_reg_off(env, reg, regno, ARG_DONTCARE); 9269 if (ret < 0) 9270 return ret; 9271 9272 if (check_mem_reg(env, reg, regno, arg->mem_size)) 9273 return -EINVAL; 9274 } else { 9275 bpf_log(log, "verifier bug: unrecognized arg#%d type %d\n", 9276 i, arg->arg_type); 9277 return -EFAULT; 9278 } 9279 } 9280 9281 return 0; 9282 } 9283 9284 /* Compare BTF of a function call with given bpf_reg_state. 9285 * Returns: 9286 * EFAULT - there is a verifier bug. Abort verification. 9287 * EINVAL - there is a type mismatch or BTF is not available. 9288 * 0 - BTF matches with what bpf_reg_state expects. 9289 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized. 9290 */ > 9291 int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog, 9292 struct bpf_reg_state *regs) 9293 { 9294 struct bpf_prog *prog = env->prog; 9295 struct btf *btf = prog->aux->btf; 9296 u32 btf_id; 9297 int err; 9298 9299 if (!prog->aux->func_info) 9300 return -EINVAL; 9301 9302 btf_id = prog->aux->func_info[subprog].type_id; 9303 if (!btf_id) 9304 return -EFAULT; 9305 9306 if (prog->aux->func_info_aux[subprog].unreliable) 9307 return -EINVAL; 9308 9309 err = btf_check_func_arg_match(env, subprog, btf, btf_id, regs); 9310 /* Compiler optimizations can remove arguments from static functions 9311 * or mismatched type can be passed into a global function. 9312 * In such cases mark the function as unreliable from BTF point of view. 9313 */ 9314 if (err) 9315 prog->aux->func_info_aux[subprog].unreliable = true; 9316 return err; 9317 } 9318 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
