netfilter: ipset: switch ext_size to atomic64_t

The hash types do not acquire set->lock, they use 'region locking' where
only part of the hash table is locked. Parallel inserts and deletes are
possible and CPUs can race on ->ext_size update.  Switch to atomic64_t.

This leaves another bug unresolved: there still can be a race on
comment extension re-init.  This will be handled in a later commit
when converting to rhashtable backend.

Fixes: f66ee0410b ("netfilter: ipset: Fix "INFO: rcu detected stall in hash_xxx" reports")
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Jozsef Kadlecsik 2026-07-30 20:38:50 +02:00 committed by Pablo Neira Ayuso
parent 8e5fd2a55e
commit 712a6f545c
5 changed files with 9 additions and 9 deletions

View File

@ -273,7 +273,7 @@ struct ip_set {
/* Number of elements (vs timeout) */
u32 elements;
/* Size of the dynamic extensions (vs timeout) */
size_t ext_size;
atomic64_t ext_size;
/* Element data size */
size_t dsize;
/* Offsets to extensions in elements */

View File

@ -77,7 +77,7 @@ mtype_flush(struct ip_set *set)
mtype_ext_cleanup(set);
bitmap_zero(map->members, map->elements);
set->elements = 0;
set->ext_size = 0;
atomic64_set(&set->ext_size, 0);
}
/* Calculate the actual memory size of the set data */
@ -93,7 +93,7 @@ mtype_head(struct ip_set *set, struct sk_buff *skb)
{
const struct mtype *map = set->data;
struct nlattr *nested;
size_t memsize = mtype_memsize(map, set->dsize) + set->ext_size;
size_t memsize = mtype_memsize(map, set->dsize) + atomic64_read(&set->ext_size);
nested = nla_nest_start(skb, IPSET_ATTR_DATA);
if (!nested)

View File

@ -350,7 +350,7 @@ ip_set_init_comment(struct ip_set *set, struct ip_set_comment *comment,
size_t len = ext->comment ? strlen(ext->comment) : 0;
if (unlikely(c)) {
set->ext_size -= sizeof(*c) + strlen(c->str) + 1;
atomic64_sub(sizeof(*c) + strlen(c->str) + 1, &set->ext_size);
rcu_assign_pointer(comment->c, NULL);
kfree_rcu(c, rcu);
}
@ -362,7 +362,7 @@ ip_set_init_comment(struct ip_set *set, struct ip_set_comment *comment,
if (unlikely(!c))
return;
strscpy(c->str, ext->comment, len + 1);
set->ext_size += sizeof(*c) + strlen(c->str) + 1;
atomic64_add(sizeof(*c) + strlen(c->str) + 1, &set->ext_size);
rcu_assign_pointer(comment->c, c);
}
EXPORT_SYMBOL_GPL(ip_set_init_comment);
@ -392,7 +392,7 @@ ip_set_comment_free(struct ip_set *set, void *ptr)
c = rcu_dereference_protected(comment->c, 1);
if (unlikely(!c))
return;
set->ext_size -= sizeof(*c) + strlen(c->str) + 1;
atomic64_sub(sizeof(*c) + strlen(c->str) + 1, &set->ext_size);
rcu_assign_pointer(comment->c, NULL);
kfree_rcu(c, rcu);
}

View File

@ -1373,7 +1373,7 @@ mtype_head(struct ip_set *set, struct sk_buff *skb)
rcu_read_lock_bh();
t = rcu_dereference_bh(h->table);
mtype_ext_size(set, &elements, &ext_size);
memsize = mtype_ahash_memsize(h, t) + ext_size + set->ext_size;
memsize = mtype_ahash_memsize(h, t) + ext_size + atomic64_read(&set->ext_size);
htable_bits = t->htable_bits;
rcu_read_unlock_bh();

View File

@ -421,7 +421,7 @@ list_set_flush(struct ip_set *set)
list_for_each_entry_safe(e, n, &map->members, list)
list_set_del(set, e);
set->elements = 0;
set->ext_size = 0;
atomic64_set(&set->ext_size, 0);
}
static void
@ -455,7 +455,7 @@ list_set_head(struct ip_set *set, struct sk_buff *skb)
{
const struct list_set *map = set->data;
struct nlattr *nested;
size_t memsize = list_set_memsize(map, set->dsize) + set->ext_size;
size_t memsize = list_set_memsize(map, set->dsize) + atomic64_read(&set->ext_size);
nested = nla_nest_start(skb, IPSET_ATTR_DATA);
if (!nested)