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 05/14] netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types
Date: Sun, 21 Jun 2026 00:27:29 +0200 [thread overview]
Message-ID: <20260620222738.112506-6-pablo@netfilter.org> (raw)
In-Reply-To: <20260620222738.112506-1-pablo@netfilter.org>
From: Jozsef Kadlecsik <kadlec@netfilter.org>
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 <kadlec@netfilter.org>
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
next prev parent reply other threads:[~2026-06-20 22:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-20 22:27 [PATCH net,v2 00/14] Netfilter fixes for net Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 01/14] netfilter: flowtable: fix offloaded ct timeout never being extended Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 02/14] netfilter: nf_queue: pin bridge device while NFQUEUE holds fake dst Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 03/14] netfilter: xt_cluster: reject template conntracks in hash match Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 04/14] netfilter: flowtable: fix and simplify IP6IP6 tunnel handling Pablo Neira Ayuso
2026-06-20 22:27 ` Pablo Neira Ayuso [this message]
2026-06-20 22:27 ` [PATCH net 06/14] netfilter: ipset: Don't use test_bit() in lockless RCU readers in bitmap types Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 07/14] netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer() Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 08/14] netfilter: ipset: make sure gc is properly stopped Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 09/14] netfilter: nft_payload: reject offsets exceeding 65535 bytes Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 10/14] netfilter: nft_meta_bridge: add validate callback for get operations Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 11/14] netfilter: nft_flow_offload: zero device address for non-ether case Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 12/14] netfilter: nf_reject: skip iphdr options when looking for icmp header Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 13/14] netfilter: nf_conntrack_expect: use conntrack GC to reap expectations Pablo Neira Ayuso
2026-06-20 22:27 ` [PATCH net 14/14] netfilter: nft_meta_bridge: fix NFT_META_BRI_IIFPVID stack leak Pablo Neira Ayuso
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