Hi Yonghong, 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/Yonghong-Song/bpf-Refactor-to-have-a-memalloc-cache-destroying-function/20231213-063401 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master patch link: https://lore.kernel.org/r/20231212223100.2138537-1-yonghong.song%40linux.dev patch subject: [PATCH bpf-next 4/5] bpf: Limit up to 512 bytes for bpf_global_percpu_ma allocation config: i386-buildonly-randconfig-001-20231213 (https://download.01.org/0day-ci/archive/20231213/202312132241.IJQpMDvO-lkp@xxxxxxxxx/config) compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231213/202312132241.IJQpMDvO-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/202312132241.IJQpMDvO-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> kernel/bpf/verifier.c:12083:21: warning: format specifies type 'unsigned long' but the argument has type 'unsigned int' [-Wformat] ret_t->size, BPF_GLOBAL_PERCPU_MA_MAX_SIZE); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/bpf/verifier.c:47:40: note: expanded from macro 'BPF_GLOBAL_PERCPU_MA_MAX_SIZE' #define BPF_GLOBAL_PERCPU_MA_MAX_SIZE (512 - LLIST_NODE_SZ) ^~~~~~~~~~~~~~~~~~~~~ 1 warning generated. vim +12083 kernel/bpf/verifier.c 11885 11886 static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, 11887 int *insn_idx_p) 11888 { 11889 const struct btf_type *t, *ptr_type; 11890 u32 i, nargs, ptr_type_id, release_ref_obj_id; 11891 struct bpf_reg_state *regs = cur_regs(env); 11892 const char *func_name, *ptr_type_name; 11893 bool sleepable, rcu_lock, rcu_unlock; 11894 struct bpf_kfunc_call_arg_meta meta; 11895 struct bpf_insn_aux_data *insn_aux; 11896 int err, insn_idx = *insn_idx_p; 11897 const struct btf_param *args; 11898 const struct btf_type *ret_t; 11899 struct btf *desc_btf; 11900 11901 /* skip for now, but return error when we find this in fixup_kfunc_call */ 11902 if (!insn->imm) 11903 return 0; 11904 11905 err = fetch_kfunc_meta(env, insn, &meta, &func_name); 11906 if (err == -EACCES && func_name) 11907 verbose(env, "calling kernel function %s is not allowed\n", func_name); 11908 if (err) 11909 return err; 11910 desc_btf = meta.btf; 11911 insn_aux = &env->insn_aux_data[insn_idx]; 11912 11913 insn_aux->is_iter_next = is_iter_next_kfunc(&meta); 11914 11915 if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) { 11916 verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n"); 11917 return -EACCES; 11918 } 11919 11920 sleepable = is_kfunc_sleepable(&meta); 11921 if (sleepable && !env->prog->aux->sleepable) { 11922 verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name); 11923 return -EACCES; 11924 } 11925 11926 /* Check the arguments */ 11927 err = check_kfunc_args(env, &meta, insn_idx); 11928 if (err < 0) 11929 return err; 11930 11931 if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { 11932 err = push_callback_call(env, insn, insn_idx, meta.subprogno, 11933 set_rbtree_add_callback_state); 11934 if (err) { 11935 verbose(env, "kfunc %s#%d failed callback verification\n", 11936 func_name, meta.func_id); 11937 return err; 11938 } 11939 } 11940 11941 rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta); 11942 rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta); 11943 11944 if (env->cur_state->active_rcu_lock) { 11945 struct bpf_func_state *state; 11946 struct bpf_reg_state *reg; 11947 u32 clear_mask = (1 << STACK_SPILL) | (1 << STACK_ITER); 11948 11949 if (in_rbtree_lock_required_cb(env) && (rcu_lock || rcu_unlock)) { 11950 verbose(env, "Calling bpf_rcu_read_{lock,unlock} in unnecessary rbtree callback\n"); 11951 return -EACCES; 11952 } 11953 11954 if (rcu_lock) { 11955 verbose(env, "nested rcu read lock (kernel function %s)\n", func_name); 11956 return -EINVAL; 11957 } else if (rcu_unlock) { 11958 bpf_for_each_reg_in_vstate_mask(env->cur_state, state, reg, clear_mask, ({ 11959 if (reg->type & MEM_RCU) { 11960 reg->type &= ~(MEM_RCU | PTR_MAYBE_NULL); 11961 reg->type |= PTR_UNTRUSTED; 11962 } 11963 })); 11964 env->cur_state->active_rcu_lock = false; 11965 } else if (sleepable) { 11966 verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name); 11967 return -EACCES; 11968 } 11969 } else if (rcu_lock) { 11970 env->cur_state->active_rcu_lock = true; 11971 } else if (rcu_unlock) { 11972 verbose(env, "unmatched rcu read unlock (kernel function %s)\n", func_name); 11973 return -EINVAL; 11974 } 11975 11976 /* In case of release function, we get register number of refcounted 11977 * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now. 11978 */ 11979 if (meta.release_regno) { 11980 err = release_reference(env, regs[meta.release_regno].ref_obj_id); 11981 if (err) { 11982 verbose(env, "kfunc %s#%d reference has not been acquired before\n", 11983 func_name, meta.func_id); 11984 return err; 11985 } 11986 } 11987 11988 if (meta.func_id == special_kfunc_list[KF_bpf_list_push_front_impl] || 11989 meta.func_id == special_kfunc_list[KF_bpf_list_push_back_impl] || 11990 meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { 11991 release_ref_obj_id = regs[BPF_REG_2].ref_obj_id; 11992 insn_aux->insert_off = regs[BPF_REG_2].off; 11993 insn_aux->kptr_struct_meta = btf_find_struct_meta(meta.arg_btf, meta.arg_btf_id); 11994 err = ref_convert_owning_non_owning(env, release_ref_obj_id); 11995 if (err) { 11996 verbose(env, "kfunc %s#%d conversion of owning ref to non-owning failed\n", 11997 func_name, meta.func_id); 11998 return err; 11999 } 12000 12001 err = release_reference(env, release_ref_obj_id); 12002 if (err) { 12003 verbose(env, "kfunc %s#%d reference has not been acquired before\n", 12004 func_name, meta.func_id); 12005 return err; 12006 } 12007 } 12008 12009 if (meta.func_id == special_kfunc_list[KF_bpf_throw]) { 12010 if (!bpf_jit_supports_exceptions()) { 12011 verbose(env, "JIT does not support calling kfunc %s#%d\n", 12012 func_name, meta.func_id); 12013 return -ENOTSUPP; 12014 } 12015 env->seen_exception = true; 12016 12017 /* In the case of the default callback, the cookie value passed 12018 * to bpf_throw becomes the return value of the program. 12019 */ 12020 if (!env->exception_callback_subprog) { 12021 err = check_return_code(env, BPF_REG_1, "R1"); 12022 if (err < 0) 12023 return err; 12024 } 12025 } 12026 12027 for (i = 0; i < CALLER_SAVED_REGS; i++) 12028 mark_reg_not_init(env, regs, caller_saved[i]); 12029 12030 /* Check return type */ 12031 t = btf_type_skip_modifiers(desc_btf, meta.func_proto->type, NULL); 12032 12033 if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) { 12034 /* Only exception is bpf_obj_new_impl */ 12035 if (meta.btf != btf_vmlinux || 12036 (meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl] && 12037 meta.func_id != special_kfunc_list[KF_bpf_percpu_obj_new_impl] && 12038 meta.func_id != special_kfunc_list[KF_bpf_refcount_acquire_impl])) { 12039 verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n"); 12040 return -EINVAL; 12041 } 12042 } 12043 12044 if (btf_type_is_scalar(t)) { 12045 mark_reg_unknown(env, regs, BPF_REG_0); 12046 mark_btf_func_reg_size(env, BPF_REG_0, t->size); 12047 } else if (btf_type_is_ptr(t)) { 12048 ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id); 12049 12050 if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) { 12051 if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl] || 12052 meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { 12053 struct btf_struct_meta *struct_meta; 12054 struct btf *ret_btf; 12055 u32 ret_btf_id; 12056 12057 if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl] && !bpf_global_ma_set) 12058 return -ENOMEM; 12059 12060 if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) { 12061 verbose(env, "local type ID argument must be in range [0, U32_MAX]\n"); 12062 return -EINVAL; 12063 } 12064 12065 ret_btf = env->prog->aux->btf; 12066 ret_btf_id = meta.arg_constant.value; 12067 12068 /* This may be NULL due to user not supplying a BTF */ 12069 if (!ret_btf) { 12070 verbose(env, "bpf_obj_new/bpf_percpu_obj_new requires prog BTF\n"); 12071 return -EINVAL; 12072 } 12073 12074 ret_t = btf_type_by_id(ret_btf, ret_btf_id); 12075 if (!ret_t || !__btf_type_is_struct(ret_t)) { 12076 verbose(env, "bpf_obj_new/bpf_percpu_obj_new type ID argument must be of a struct\n"); 12077 return -EINVAL; 12078 } 12079 12080 if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { 12081 if (ret_t->size > BPF_GLOBAL_PERCPU_MA_MAX_SIZE) { 12082 verbose(env, "bpf_percpu_obj_new type size (%d) is greater than %lu\n", 12083 ret_t->size, BPF_GLOBAL_PERCPU_MA_MAX_SIZE); 12084 return -EINVAL; 12085 } 12086 mutex_lock(&bpf_percpu_ma_lock); 12087 err = bpf_mem_alloc_percpu_unit_init(&bpf_global_percpu_ma, ret_t->size); 12088 mutex_unlock(&bpf_percpu_ma_lock); 12089 if (err) 12090 return err; 12091 } 12092 12093 struct_meta = btf_find_struct_meta(ret_btf, ret_btf_id); 12094 if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { 12095 if (!__btf_type_is_scalar_struct(env, ret_btf, ret_t, 0)) { 12096 verbose(env, "bpf_percpu_obj_new type ID argument must be of a struct of scalars\n"); 12097 return -EINVAL; 12098 } 12099 12100 if (struct_meta) { 12101 verbose(env, "bpf_percpu_obj_new type ID argument must not contain special fields\n"); 12102 return -EINVAL; 12103 } 12104 } 12105 12106 mark_reg_known_zero(env, regs, BPF_REG_0); 12107 regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; 12108 regs[BPF_REG_0].btf = ret_btf; 12109 regs[BPF_REG_0].btf_id = ret_btf_id; 12110 if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) 12111 regs[BPF_REG_0].type |= MEM_PERCPU; 12112 12113 insn_aux->obj_new_size = ret_t->size; 12114 insn_aux->kptr_struct_meta = struct_meta; 12115 } else if (meta.func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) { 12116 mark_reg_known_zero(env, regs, BPF_REG_0); 12117 regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; 12118 regs[BPF_REG_0].btf = meta.arg_btf; 12119 regs[BPF_REG_0].btf_id = meta.arg_btf_id; 12120 12121 insn_aux->kptr_struct_meta = 12122 btf_find_struct_meta(meta.arg_btf, 12123 meta.arg_btf_id); 12124 } else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] || 12125 meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) { 12126 struct btf_field *field = meta.arg_list_head.field; 12127 12128 mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); 12129 } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_remove] || 12130 meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) { 12131 struct btf_field *field = meta.arg_rbtree_root.field; 12132 12133 mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); 12134 } else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { 12135 mark_reg_known_zero(env, regs, BPF_REG_0); 12136 regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED; 12137 regs[BPF_REG_0].btf = desc_btf; 12138 regs[BPF_REG_0].btf_id = meta.ret_btf_id; 12139 } else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { 12140 ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value); 12141 if (!ret_t || !btf_type_is_struct(ret_t)) { 12142 verbose(env, 12143 "kfunc bpf_rdonly_cast type ID argument must be of a struct\n"); 12144 return -EINVAL; 12145 } 12146 12147 mark_reg_known_zero(env, regs, BPF_REG_0); 12148 regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED; 12149 regs[BPF_REG_0].btf = desc_btf; 12150 regs[BPF_REG_0].btf_id = meta.arg_constant.value; 12151 } else if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice] || 12152 meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) { 12153 enum bpf_type_flag type_flag = get_dynptr_type_flag(meta.initialized_dynptr.type); 12154 12155 mark_reg_known_zero(env, regs, BPF_REG_0); 12156 12157 if (!meta.arg_constant.found) { 12158 verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n"); 12159 return -EFAULT; 12160 } 12161 12162 regs[BPF_REG_0].mem_size = meta.arg_constant.value; 12163 12164 /* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */ 12165 regs[BPF_REG_0].type = PTR_TO_MEM | type_flag; 12166 12167 if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice]) { 12168 regs[BPF_REG_0].type |= MEM_RDONLY; 12169 } else { 12170 /* this will set env->seen_direct_write to true */ 12171 if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) { 12172 verbose(env, "the prog does not allow writes to packet data\n"); 12173 return -EINVAL; 12174 } 12175 } 12176 12177 if (!meta.initialized_dynptr.id) { 12178 verbose(env, "verifier internal error: no dynptr id\n"); 12179 return -EFAULT; 12180 } 12181 regs[BPF_REG_0].dynptr_id = meta.initialized_dynptr.id; 12182 12183 /* we don't need to set BPF_REG_0's ref obj id 12184 * because packet slices are not refcounted (see 12185 * dynptr_type_refcounted) 12186 */ 12187 } else { 12188 verbose(env, "kernel function %s unhandled dynamic return type\n", 12189 meta.func_name); 12190 return -EFAULT; 12191 } 12192 } else if (!__btf_type_is_struct(ptr_type)) { 12193 if (!meta.r0_size) { 12194 __u32 sz; 12195 12196 if (!IS_ERR(btf_resolve_size(desc_btf, ptr_type, &sz))) { 12197 meta.r0_size = sz; 12198 meta.r0_rdonly = true; 12199 } 12200 } 12201 if (!meta.r0_size) { 12202 ptr_type_name = btf_name_by_offset(desc_btf, 12203 ptr_type->name_off); 12204 verbose(env, 12205 "kernel function %s returns pointer type %s %s is not supported\n", 12206 func_name, 12207 btf_type_str(ptr_type), 12208 ptr_type_name); 12209 return -EINVAL; 12210 } 12211 12212 mark_reg_known_zero(env, regs, BPF_REG_0); 12213 regs[BPF_REG_0].type = PTR_TO_MEM; 12214 regs[BPF_REG_0].mem_size = meta.r0_size; 12215 12216 if (meta.r0_rdonly) 12217 regs[BPF_REG_0].type |= MEM_RDONLY; 12218 12219 /* Ensures we don't access the memory after a release_reference() */ 12220 if (meta.ref_obj_id) 12221 regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id; 12222 } else { 12223 mark_reg_known_zero(env, regs, BPF_REG_0); 12224 regs[BPF_REG_0].btf = desc_btf; 12225 regs[BPF_REG_0].type = PTR_TO_BTF_ID; 12226 regs[BPF_REG_0].btf_id = ptr_type_id; 12227 } 12228 12229 if (is_kfunc_ret_null(&meta)) { 12230 regs[BPF_REG_0].type |= PTR_MAYBE_NULL; 12231 /* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */ 12232 regs[BPF_REG_0].id = ++env->id_gen; 12233 } 12234 mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *)); 12235 if (is_kfunc_acquire(&meta)) { 12236 int id = acquire_reference_state(env, insn_idx); 12237 12238 if (id < 0) 12239 return id; 12240 if (is_kfunc_ret_null(&meta)) 12241 regs[BPF_REG_0].id = id; 12242 regs[BPF_REG_0].ref_obj_id = id; 12243 } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) { 12244 ref_set_non_owning(env, ®s[BPF_REG_0]); 12245 } 12246 12247 if (reg_may_point_to_spin_lock(®s[BPF_REG_0]) && !regs[BPF_REG_0].id) 12248 regs[BPF_REG_0].id = ++env->id_gen; 12249 } else if (btf_type_is_void(t)) { 12250 if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) { 12251 if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl] || 12252 meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_drop_impl]) { 12253 insn_aux->kptr_struct_meta = 12254 btf_find_struct_meta(meta.arg_btf, 12255 meta.arg_btf_id); 12256 } 12257 } 12258 } 12259 12260 nargs = btf_type_vlen(meta.func_proto); 12261 args = (const struct btf_param *)(meta.func_proto + 1); 12262 for (i = 0; i < nargs; i++) { 12263 u32 regno = i + 1; 12264 12265 t = btf_type_skip_modifiers(desc_btf, args[i].type, NULL); 12266 if (btf_type_is_ptr(t)) 12267 mark_btf_func_reg_size(env, regno, sizeof(void *)); 12268 else 12269 /* scalar. ensured by btf_check_kfunc_arg_match() */ 12270 mark_btf_func_reg_size(env, regno, t->size); 12271 } 12272 12273 if (is_iter_next_kfunc(&meta)) { 12274 err = process_iter_next_call(env, insn_idx, &meta); 12275 if (err) 12276 return err; 12277 } 12278 12279 return 0; 12280 } 12281 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
