From e4b4984e28c16406ecb318444dea4a8bf47def3e Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Wed, 17 Jun 2026 10:41:22 +0200 Subject: [PATCH] netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types Sashiko pointed out that there are a few lockless RCU readers using test_bit() which is a relaxed atomic operation and provides no memory barrier guarantees. Use test_bit_acquire() instead where the operation may run parallel with add/del/gc, i.e. is not one from the next cases - protected by region lock - in a set destroy phase - in a new/temporary set creation phase Fixes: 18f84d41d34f ("netfilter: ipset: Introduce RCU locking in hash:* types") Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso --- net/netfilter/ipset/ip_set_hash_gen.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h index 04e4627ddfc1..00c27b95207f 100644 --- a/net/netfilter/ipset/ip_set_hash_gen.h +++ b/net/netfilter/ipset/ip_set_hash_gen.h @@ -689,7 +689,7 @@ mtype_resize(struct ip_set *set, bool retried) continue; pos = smp_load_acquire(&n->pos); for (j = 0; j < pos; j++) { - if (!test_bit(j, n->used)) + if (!test_bit_acquire(j, n->used)) continue; data = ahash_data(n, j, dsize); if (SET_ELEM_EXPIRED(set, data)) @@ -826,7 +826,7 @@ mtype_ext_size(struct ip_set *set, u32 *elements, size_t *ext_size) continue; pos = smp_load_acquire(&n->pos); for (j = 0; j < pos; j++) { - if (!test_bit(j, n->used)) + if (!test_bit_acquire(j, n->used)) continue; data = ahash_data(n, j, set->dsize); if (!SET_ELEM_EXPIRED(set, data)) @@ -1201,7 +1201,7 @@ mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d, continue; pos = smp_load_acquire(&n->pos); for (i = 0; i < pos; i++) { - if (!test_bit(i, n->used)) + if (!test_bit_acquire(i, n->used)) continue; data = ahash_data(n, i, set->dsize); if (!mtype_data_equal(data, d, &multi)) @@ -1259,7 +1259,7 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext, } pos = smp_load_acquire(&n->pos); for (i = 0; i < pos; i++) { - if (!test_bit(i, n->used)) + if (!test_bit_acquire(i, n->used)) continue; data = ahash_data(n, i, set->dsize); if (!mtype_data_equal(data, d, &multi)) @@ -1396,7 +1396,7 @@ mtype_list(const struct ip_set *set, continue; pos = smp_load_acquire(&n->pos); for (i = 0; i < pos; i++) { - if (!test_bit(i, n->used)) + if (!test_bit_acquire(i, n->used)) continue; e = ahash_data(n, i, set->dsize); if (SET_ELEM_EXPIRED(set, e))