Hello Florian Westphal,
Commit 17a20e09f086 ("netfilter: nft_set: remove one argument from
lookup and update functions") from Jul 9, 2025 (linux-next), leads to
the following Smatch static checker warning:
net/netfilter/nft_set_pipapo_avx2.c:1269 nft_pipapo_avx2_lookup()
error: uninitialized symbol 'ext'.
net/netfilter/nft_set_pipapo_avx2.c
1148 const struct nft_set_ext *
1149 nft_pipapo_avx2_lookup(const struct net *net, const struct nft_set *set,
1150 const u32 *key)
1151 {
1152 struct nft_pipapo *priv = nft_set_priv(set);
1153 struct nft_pipapo_scratch *scratch;
1154 u8 genmask = nft_genmask_cur(net);
1155 const struct nft_pipapo_match *m;
1156 const struct nft_pipapo_field *f;
1157 const u8 *rp = (const u8 *)key;
1158 const struct nft_set_ext *ext;
1159 unsigned long *res, *fill;
1160 bool map_index;
1161 int i;
1162
1163 local_bh_disable();
1164
1165 if (unlikely(!irq_fpu_usable())) {
1166 ext = nft_pipapo_lookup(net, set, key);
1167
1168 local_bh_enable();
1169 return ext;
1170 }
1171
1172 m = rcu_dereference(priv->match);
1173
1174 /* This also protects access to all data related to scratch maps.
1175 *
1176 * Note that we don't need a valid MXCSR state for any of the
1177 * operations we use here, so pass 0 as mask and spare a LDMXCSR
1178 * instruction.
1179 */
1180 kernel_fpu_begin_mask(0);
1181
1182 scratch = *raw_cpu_ptr(m->scratch);
1183 if (unlikely(!scratch)) {
1184 kernel_fpu_end();
1185 local_bh_enable();
1186 return NULL;
1187 }
1188
1189 map_index = scratch->map_index;
1190
1191 res = scratch->map + (map_index ? m->bsize_max : 0);
1192 fill = scratch->map + (map_index ? 0 : m->bsize_max);
1193
1194 pipapo_resmap_init_avx2(m, res);
1195
1196 nft_pipapo_avx2_prepare();
1197
1198 next_match:
1199 nft_pipapo_for_each_field(f, i, m) {
1200 bool last = i == m->field_count - 1, first = !i;
1201 int ret = 0;
1202
1203 #define NFT_SET_PIPAPO_AVX2_LOOKUP(b, n) \
1204 (ret = nft_pipapo_avx2_lookup_##b##b_##n(res, fill, f, \
1205 ret, rp, \
1206 first, last))
1207
1208 if (likely(f->bb == 8)) {
1209 if (f->groups == 1) {
1210 NFT_SET_PIPAPO_AVX2_LOOKUP(8, 1);
1211 } else if (f->groups == 2) {
1212 NFT_SET_PIPAPO_AVX2_LOOKUP(8, 2);
1213 } else if (f->groups == 4) {
1214 NFT_SET_PIPAPO_AVX2_LOOKUP(8, 4);
1215 } else if (f->groups == 6) {
1216 NFT_SET_PIPAPO_AVX2_LOOKUP(8, 6);
1217 } else if (f->groups == 16) {
1218 NFT_SET_PIPAPO_AVX2_LOOKUP(8, 16);
1219 } else {
1220 ret = nft_pipapo_avx2_lookup_slow(m, res, fill, f,
1221 ret, rp,
1222 first, last);
1223 }
1224 } else {
1225 if (f->groups == 2) {
1226 NFT_SET_PIPAPO_AVX2_LOOKUP(4, 2);
1227 } else if (f->groups == 4) {
1228 NFT_SET_PIPAPO_AVX2_LOOKUP(4, 4);
1229 } else if (f->groups == 8) {
1230 NFT_SET_PIPAPO_AVX2_LOOKUP(4, 8);
1231 } else if (f->groups == 12) {
1232 NFT_SET_PIPAPO_AVX2_LOOKUP(4, 12);
1233 } else if (f->groups == 32) {
1234 NFT_SET_PIPAPO_AVX2_LOOKUP(4, 32);
1235 } else {
1236 ret = nft_pipapo_avx2_lookup_slow(m, res, fill, f,
1237 ret, rp,
1238 first, last);
1239 }
1240 }
1241 NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4;
1242
1243 #undef NFT_SET_PIPAPO_AVX2_LOOKUP
1244
1245 if (ret < 0)
1246 goto out;
Needs an "ext = NULL;"?
1247
1248 if (last) {
1249 ext = &f->mt[ret].e->ext;
1250 if (unlikely(nft_set_elem_expired(ext) ||
1251 !nft_set_elem_active(ext, genmask))) {
1252 ext = NULL;
1253 goto next_match;
1254 }
1255
1256 goto out;
1257 }
1258
1259 swap(res, fill);
1260 rp += NFT_PIPAPO_GROUPS_PADDED_SIZE(f);
1261 }
1262
1263 out:
1264 if (i % 2)
1265 scratch->map_index = !map_index;
1266 kernel_fpu_end();
1267 local_bh_enable();
1268
--> 1269 return ext;
1270 }
regards,
dan carpenter
