[PATCH net 06/16] netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2026-06-19 11:55:10
Also in:
netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Jozsef Kadlecsik <redacted>
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 <redacted>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
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))
--
2.47.3