Re: [PATCH bpf-next v3 1/4] bpf: Generalize bpf_sk_storage

From: kernel test robot
Date: Wed Jul 08 2020 - 23:44:58 EST

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In reply to: KP Singh: "[PATCH bpf-next v3 1/4] bpf: Generalize bpf_sk_storage"
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Hi KP,

I love your patch! Perhaps something to improve:

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

url: https://github.com/0day-ci/linux/commits/KP-Singh/Generalizing-bpf_local_storage/20200709-085810
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: alpha-allyesconfig (attached as .config)
compiler: alpha-linux-gcc (GCC) 9.3.0
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
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=alpha

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> net/core/bpf_sk_storage.c:170:6: warning: no previous prototype for 'bpf_sk_storage_free' [-Wmissing-prototypes]
170 | void bpf_sk_storage_free(struct sock *sk)
| ^~~~~~~~~~~~~~~~~~~
>> net/core/bpf_sk_storage.c:280:5: warning: no previous prototype for 'bpf_sk_storage_clone' [-Wmissing-prototypes]
280 | int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
| ^~~~~~~~~~~~~~~~~~~~
>> net/core/bpf_sk_storage.c:401:17: warning: no previous prototype for 'sk_storage_map_alloc' [-Wmissing-prototypes]
401 | struct bpf_map *sk_storage_map_alloc(union bpf_attr *attr)
| ^~~~~~~~~~~~~~~~~~~~
>> net/core/bpf_sk_storage.c:413:6: warning: no previous prototype for 'sk_storage_map_free' [-Wmissing-prototypes]
413 | void sk_storage_map_free(struct bpf_map *map)
| ^~~~~~~~~~~~~~~~~~~
>> net/core/bpf_sk_storage.c:483:6: warning: no previous prototype for 'bpf_sk_storage_diag_free' [-Wmissing-prototypes]
483 | void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag)
| ^~~~~~~~~~~~~~~~~~~~~~~~
>> net/core/bpf_sk_storage.c:511:1: warning: no previous prototype for 'bpf_sk_storage_diag_alloc' [-Wmissing-prototypes]
511 | bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
>> net/core/bpf_sk_storage.c:658:5: warning: no previous prototype for 'bpf_sk_storage_diag_put' [-Wmissing-prototypes]
658 | int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
| ^~~~~~~~~~~~~~~~~~~~~~~

vim +/bpf_sk_storage_free +170 net/core/bpf_sk_storage.c

6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 168
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 169 /* Called by __sk_destruct() & bpf_sk_storage_clone() */
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 @170 void bpf_sk_storage_free(struct sock *sk)
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 171 {
9af362a775d83f KP Singh 2020-07-09 172 struct bpf_local_storage_elem *selem;
9af362a775d83f KP Singh 2020-07-09 173 struct bpf_local_storage *sk_storage;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 174 bool free_sk_storage = false;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 175 struct hlist_node *n;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 176
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 177 rcu_read_lock();
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 178 sk_storage = rcu_dereference(sk->sk_bpf_storage);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 179 if (!sk_storage) {
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 180 rcu_read_unlock();
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 181 return;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 182 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 183
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 184 /* Netiher the bpf_prog nor the bpf-map's syscall
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 185 * could be modifying the sk_storage->list now.
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 186 * Thus, no elem can be added-to or deleted-from the
9af362a775d83f KP Singh 2020-07-09 187 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 188 *
9af362a775d83f KP Singh 2020-07-09 189 * It is racing with bpf_local_storage_map_free() alone
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 190 * when unlinking elem from the sk_storage->list and
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 191 * the map's bucket->list.
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 192 */
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 193 raw_spin_lock_bh(&sk_storage->lock);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 194 hlist_for_each_entry_safe(selem, n, &sk_storage->list, snode) {
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 195 /* Always unlink from map before unlinking from
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 196 * sk_storage.
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 197 */
9af362a775d83f KP Singh 2020-07-09 198 bpf_selem_unlink_map(selem);
9af362a775d83f KP Singh 2020-07-09 199 free_sk_storage = bpf_selem_unlink(sk_storage, selem, true);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 200 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 201 raw_spin_unlock_bh(&sk_storage->lock);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 202 rcu_read_unlock();
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 203
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 204 if (free_sk_storage)
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 205 kfree_rcu(sk_storage, rcu);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 206 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 207
9af362a775d83f KP Singh 2020-07-09 208 static void *bpf_sk_storage_lookup_elem(struct bpf_map *map, void *key)
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 209 {
9af362a775d83f KP Singh 2020-07-09 210 struct bpf_local_storage_data *sdata;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 211 struct socket *sock;
9af362a775d83f KP Singh 2020-07-09 212 int fd, err = -EINVAL;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 213
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 214 fd = *(int *)key;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 215 sock = sockfd_lookup(fd, &err);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 216 if (sock) {
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 217 sdata = sk_storage_lookup(sock->sk, map, true);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 218 sockfd_put(sock);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 219 return sdata ? sdata->data : NULL;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 220 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 221
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 222 return ERR_PTR(err);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 223 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 224
9af362a775d83f KP Singh 2020-07-09 225 static int bpf_sk_storage_update_elem(struct bpf_map *map, void *key,
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 226 void *value, u64 map_flags)
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 227 {
9af362a775d83f KP Singh 2020-07-09 228 struct bpf_local_storage_data *sdata;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 229 struct socket *sock;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 230 int fd, err;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 231
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 232 fd = *(int *)key;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 233 sock = sockfd_lookup(fd, &err);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 234 if (sock) {
9af362a775d83f KP Singh 2020-07-09 235 sdata = map->ops->map_local_storage_update(sock->sk, map, value,
9af362a775d83f KP Singh 2020-07-09 236 map_flags);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 237 sockfd_put(sock);
71f150f4c2af5f YueHaibing 2019-04-29 238 return PTR_ERR_OR_ZERO(sdata);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 239 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 240
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 241 return err;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 242 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 243
9af362a775d83f KP Singh 2020-07-09 244 static int bpf_sk_storage_delete_elem(struct bpf_map *map, void *key)
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 245 {
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 246 struct socket *sock;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 247 int fd, err;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 248
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 249 fd = *(int *)key;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 250 sock = sockfd_lookup(fd, &err);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 251 if (sock) {
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 252 err = sk_storage_delete(sock->sk, map);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 253 sockfd_put(sock);
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 254 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 255
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 256 return err;
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 257 }
6ac99e8f23d4b1 Martin KaFai Lau 2019-04-26 258
9af362a775d83f KP Singh 2020-07-09 259 static struct bpf_local_storage_elem *
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 260 bpf_sk_storage_clone_elem(struct sock *newsk,
9af362a775d83f KP Singh 2020-07-09 261 struct bpf_local_storage_map *smap,
9af362a775d83f KP Singh 2020-07-09 262 struct bpf_local_storage_elem *selem)
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 263 {
9af362a775d83f KP Singh 2020-07-09 264 struct bpf_local_storage_elem *copy_selem;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 265
9af362a775d83f KP Singh 2020-07-09 266 copy_selem = sk_selem_alloc(smap, newsk, NULL, true);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 267 if (!copy_selem)
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 268 return NULL;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 269
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 270 if (map_value_has_spin_lock(&smap->map))
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 271 copy_map_value_locked(&smap->map, SDATA(copy_selem)->data,
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 272 SDATA(selem)->data, true);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 273 else
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 274 copy_map_value(&smap->map, SDATA(copy_selem)->data,
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 275 SDATA(selem)->data);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 276
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 277 return copy_selem;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 278 }
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 279
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 @280 int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 281 {
9af362a775d83f KP Singh 2020-07-09 282 struct bpf_local_storage *new_sk_storage = NULL;
9af362a775d83f KP Singh 2020-07-09 283 struct bpf_local_storage *sk_storage;
9af362a775d83f KP Singh 2020-07-09 284 struct bpf_local_storage_elem *selem;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 285 int ret = 0;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 286
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 287 RCU_INIT_POINTER(newsk->sk_bpf_storage, NULL);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 288
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 289 rcu_read_lock();
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 290 sk_storage = rcu_dereference(sk->sk_bpf_storage);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 291
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 292 if (!sk_storage || hlist_empty(&sk_storage->list))
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 293 goto out;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 294
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 295 hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) {
9af362a775d83f KP Singh 2020-07-09 296 struct bpf_local_storage_elem *copy_selem;
9af362a775d83f KP Singh 2020-07-09 297 struct bpf_local_storage_map *smap;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 298 struct bpf_map *map;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 299
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 300 smap = rcu_dereference(SDATA(selem)->smap);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 301 if (!(smap->map.map_flags & BPF_F_CLONE))
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 302 continue;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 303
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 304 /* Note that for lockless listeners adding new element
9af362a775d83f KP Singh 2020-07-09 305 * here can race with cleanup in bpf_local_storage_map_free.
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 306 * Try to grab map refcnt to make sure that it's still
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 307 * alive and prevent concurrent removal.
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 308 */
1e0bd5a091e5d9 Andrii Nakryiko 2019-11-17 309 map = bpf_map_inc_not_zero(&smap->map);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 310 if (IS_ERR(map))
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 311 continue;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 312
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 313 copy_selem = bpf_sk_storage_clone_elem(newsk, smap, selem);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 314 if (!copy_selem) {
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 315 ret = -ENOMEM;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 316 bpf_map_put(map);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 317 goto out;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 318 }
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 319
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 320 if (new_sk_storage) {
9af362a775d83f KP Singh 2020-07-09 321 bpf_selem_link_map(smap, copy_selem);
9af362a775d83f KP Singh 2020-07-09 322 bpf_selem_link(new_sk_storage, copy_selem);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 323 } else {
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 324 ret = sk_storage_alloc(newsk, smap, copy_selem);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 325 if (ret) {
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 326 kfree(copy_selem);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 327 atomic_sub(smap->elem_size,
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 328 &newsk->sk_omem_alloc);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 329 bpf_map_put(map);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 330 goto out;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 331 }
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 332
9af362a775d83f KP Singh 2020-07-09 333 new_sk_storage =
9af362a775d83f KP Singh 2020-07-09 334 rcu_dereference(copy_selem->local_storage);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 335 }
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 336 bpf_map_put(map);
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 337 }
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 338
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 339 out:
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 340 rcu_read_unlock();
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 341
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 342 /* In case of an error, don't free anything explicitly here, the
9af362a775d83f KP Singh 2020-07-09 343 * caller is responsible to call bpf_local_storage_free.
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 344 */
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 345
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 346 return ret;
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 347 }
8f51dfc73bf181 Stanislav Fomichev 2019-08-14 348

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In reply to: KP Singh: "[PATCH bpf-next v3 1/4] bpf: Generalize bpf_sk_storage"
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