From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org,
pabeni@redhat.com, edumazet@google.com, fw@strlen.de,
horms@kernel.org
Subject: [PATCH net 10/12] netfilter: ipset: annotate "pos" for concurrent readers/writers
Date: Sat, 16 May 2026 13:56:25 +0200 [thread overview]
Message-ID: <20260516115627.967773-11-pablo@netfilter.org> (raw)
In-Reply-To: <20260516115627.967773-1-pablo@netfilter.org>
From: Jozsef Kadlecsik <kadlec@netfilter.org>
The "pos" structure member of struct hbucket stores the first
free slot in the hash bucket of a hash type of set and there
are concurrent readers/writers. Annotate accesses properly.
Fixes: 18f84d41d34f ("netfilter: ipset: Introduce RCU locking in hash:* types")
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/ipset/ip_set_hash_gen.h | 62 ++++++++++++++++-----------
1 file changed, 38 insertions(+), 24 deletions(-)
diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index 133ce4611eed..04e4627ddfc1 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -386,8 +386,9 @@ static void
mtype_ext_cleanup(struct ip_set *set, struct hbucket *n)
{
int i;
+ u8 pos = smp_load_acquire(&n->pos);
- for (i = 0; i < n->pos; i++)
+ for (i = 0; i < pos; i++)
if (test_bit(i, n->used))
ip_set_ext_destroy(set, ahash_data(n, i, set->dsize));
}
@@ -490,7 +491,7 @@ mtype_gc_do(struct ip_set *set, struct htype *h, struct htable *t, u32 r)
#ifdef IP_SET_HASH_WITH_NETS
u8 k;
#endif
- u8 htable_bits = t->htable_bits;
+ u8 pos, htable_bits = t->htable_bits;
spin_lock_bh(&t->hregion[r].lock);
for (i = ahash_bucket_start(r, htable_bits);
@@ -498,7 +499,8 @@ mtype_gc_do(struct ip_set *set, struct htype *h, struct htable *t, u32 r)
n = __ipset_dereference(hbucket(t, i));
if (!n)
continue;
- for (j = 0, d = 0; j < n->pos; j++) {
+ pos = smp_load_acquire(&n->pos);
+ for (j = 0, d = 0; j < pos; j++) {
if (!test_bit(j, n->used)) {
d++;
continue;
@@ -534,7 +536,7 @@ mtype_gc_do(struct ip_set *set, struct htype *h, struct htable *t, u32 r)
/* Still try to delete expired elements. */
continue;
tmp->size = n->size - AHASH_INIT_SIZE;
- for (j = 0, d = 0; j < n->pos; j++) {
+ for (j = 0, d = 0; j < pos; j++) {
if (!test_bit(j, n->used))
continue;
data = ahash_data(n, j, dsize);
@@ -623,7 +625,7 @@ mtype_resize(struct ip_set *set, bool retried)
{
struct htype *h = set->data;
struct htable *t, *orig;
- u8 htable_bits;
+ u8 pos, htable_bits;
size_t hsize, dsize = set->dsize;
#ifdef IP_SET_HASH_WITH_NETS
u8 flags;
@@ -685,7 +687,8 @@ mtype_resize(struct ip_set *set, bool retried)
n = __ipset_dereference(hbucket(orig, i));
if (!n)
continue;
- for (j = 0; j < n->pos; j++) {
+ pos = smp_load_acquire(&n->pos);
+ for (j = 0; j < pos; j++) {
if (!test_bit(j, n->used))
continue;
data = ahash_data(n, j, dsize);
@@ -809,9 +812,10 @@ mtype_ext_size(struct ip_set *set, u32 *elements, size_t *ext_size)
{
struct htype *h = set->data;
const struct htable *t;
- u32 i, j, r;
struct hbucket *n;
struct mtype_elem *data;
+ u32 i, j, r;
+ u8 pos;
t = rcu_dereference_bh(h->table);
for (r = 0; r < ahash_numof_locks(t->htable_bits); r++) {
@@ -820,7 +824,8 @@ mtype_ext_size(struct ip_set *set, u32 *elements, size_t *ext_size)
n = rcu_dereference_bh(hbucket(t, i));
if (!n)
continue;
- for (j = 0; j < n->pos; j++) {
+ pos = smp_load_acquire(&n->pos);
+ for (j = 0; j < pos; j++) {
if (!test_bit(j, n->used))
continue;
data = ahash_data(n, j, set->dsize);
@@ -844,10 +849,11 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
const struct mtype_elem *d = value;
struct mtype_elem *data;
struct hbucket *n, *old = ERR_PTR(-ENOENT);
- int i, j = -1, npos = 0, ret;
+ int i, j = -1, ret;
bool flag_exist = flags & IPSET_FLAG_EXIST;
bool deleted = false, forceadd = false, reuse = false;
u32 r, key, multi = 0, elements, maxelem;
+ u8 npos = 0;
rcu_read_lock_bh();
t = rcu_dereference_bh(h->table);
@@ -889,8 +895,8 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
ext_size(AHASH_INIT_SIZE, set->dsize);
goto copy_elem;
}
- npos = n->pos;
- for (i = 0; i < n->pos; i++) {
+ npos = smp_load_acquire(&n->pos);
+ for (i = 0; i < npos; i++) {
if (!test_bit(i, n->used)) {
/* Reuse first deleted entry */
if (j == -1) {
@@ -934,7 +940,7 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
if (elements >= maxelem)
goto set_full;
/* Create a new slot */
- if (n->pos >= n->size) {
+ if (npos >= n->size) {
#ifdef IP_SET_HASH_WITH_MULTI
if (h->bucketsize >= AHASH_MAX_TUNED)
goto set_full;
@@ -963,8 +969,7 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
}
copy_elem:
- j = npos;
- npos = n->pos + 1;
+ j = npos++;
data = ahash_data(n, j, set->dsize);
copy_data:
t->hregion[r].elements++;
@@ -987,7 +992,8 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
if (SET_WITH_TIMEOUT(set))
ip_set_timeout_set(ext_timeout(data, set), ext->timeout);
smp_mb__before_atomic();
- n->pos = npos;
+ /* Ensure all data writes are visible before updating position */
+ smp_store_release(&n->pos, npos);
set_bit(j, n->used);
if (old != ERR_PTR(-ENOENT)) {
rcu_assign_pointer(hbucket(t, key), n);
@@ -1046,6 +1052,7 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
int i, j, k, r, ret = -IPSET_ERR_EXIST;
u32 key, multi = 0;
size_t dsize = set->dsize;
+ u8 pos;
/* Userspace add and resize is excluded by the mutex.
* Kernespace add does not trigger resize.
@@ -1061,7 +1068,8 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
n = rcu_dereference_bh(hbucket(t, key));
if (!n)
goto out;
- for (i = 0, k = 0; i < n->pos; i++) {
+ pos = smp_load_acquire(&n->pos);
+ for (i = 0, k = 0; i < pos; i++) {
if (!test_bit(i, n->used)) {
k++;
continue;
@@ -1075,8 +1083,8 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
ret = 0;
clear_bit(i, n->used);
smp_mb__after_atomic();
- if (i + 1 == n->pos)
- n->pos--;
+ if (i + 1 == pos)
+ smp_store_release(&n->pos, --pos);
t->hregion[r].elements--;
#ifdef IP_SET_HASH_WITH_NETS
for (j = 0; j < IPSET_NET_COUNT; j++)
@@ -1097,11 +1105,11 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
x->flags = flags;
}
}
- for (; i < n->pos; i++) {
+ for (; i < pos; i++) {
if (!test_bit(i, n->used))
k++;
}
- if (k == n->pos) {
+ if (k == pos) {
t->hregion[r].ext_size -= ext_size(n->size, dsize);
rcu_assign_pointer(hbucket(t, key), NULL);
kfree_rcu(n, rcu);
@@ -1112,7 +1120,7 @@ mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
if (!tmp)
goto out;
tmp->size = n->size - AHASH_INIT_SIZE;
- for (j = 0, k = 0; j < n->pos; j++) {
+ for (j = 0, k = 0; j < pos; j++) {
if (!test_bit(j, n->used))
continue;
data = ahash_data(n, j, dsize);
@@ -1173,6 +1181,7 @@ mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d,
int ret, i, j = 0;
#endif
u32 key, multi = 0;
+ u8 pos;
pr_debug("test by nets\n");
for (; j < NLEN && h->nets[j].cidr[0] && !multi; j++) {
@@ -1190,7 +1199,8 @@ mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d,
n = rcu_dereference_bh(hbucket(t, key));
if (!n)
continue;
- for (i = 0; i < n->pos; i++) {
+ pos = smp_load_acquire(&n->pos);
+ for (i = 0; i < pos; i++) {
if (!test_bit(i, n->used))
continue;
data = ahash_data(n, i, set->dsize);
@@ -1224,6 +1234,7 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
struct mtype_elem *data;
int i, ret = 0;
u32 key, multi = 0;
+ u8 pos;
rcu_read_lock_bh();
t = rcu_dereference_bh(h->table);
@@ -1246,7 +1257,8 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
ret = 0;
goto out;
}
- for (i = 0; i < n->pos; i++) {
+ pos = smp_load_acquire(&n->pos);
+ for (i = 0; i < pos; i++) {
if (!test_bit(i, n->used))
continue;
data = ahash_data(n, i, set->dsize);
@@ -1363,6 +1375,7 @@ mtype_list(const struct ip_set *set,
/* We assume that one hash bucket fills into one page */
void *incomplete;
int i, ret = 0;
+ u8 pos;
atd = nla_nest_start(skb, IPSET_ATTR_ADT);
if (!atd)
@@ -1381,7 +1394,8 @@ mtype_list(const struct ip_set *set,
cb->args[IPSET_CB_ARG0], t, n);
if (!n)
continue;
- for (i = 0; i < n->pos; i++) {
+ pos = smp_load_acquire(&n->pos);
+ for (i = 0; i < pos; i++) {
if (!test_bit(i, n->used))
continue;
e = ahash_data(n, i, set->dsize);
--
2.47.3
next prev parent reply other threads:[~2026-05-16 11:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-16 11:56 [PATCH net 00/12] Netfilter/IPVS fixes for net Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 01/12] netfilter: nf_conntrack_helper: fix possible null deref during error log Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 02/12] ipvs: avoid possible loop in ip_vs_dst_event on resizing Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 03/12] netfilter: ipset: fix a potential dump-destroy race Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 04/12] netfilter: nft_inner: Fix IPv6 inner_thoff desync Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 05/12] netfilter: ipset: stop hash:* range iteration at end Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 06/12] netfilter: nft_inner: release local_lock before re-enabling softirqs Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 07/12] netfilter: ip6t_hbh: reject oversized option lists Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 08/12] netfilter: ipset: Fix data race between add and list header in all hash types Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 09/12] netfilter: ipset: Fix data race between add and dump " Pablo Neira Ayuso
2026-05-16 11:56 ` Pablo Neira Ayuso [this message]
2026-05-16 11:56 ` [PATCH net 11/12] netfilter: br_netfilter: Reallocate headroom if necessary in neigh_hh_bridge() Pablo Neira Ayuso
2026-05-16 11:56 ` [PATCH net 12/12] netfilter: nf_queue: hold bridge skb->dev while queued Pablo Neira Ayuso
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