From: Linkui Xiao <xiaolinkui@xxxxxxxxxx> If the ip_set is not locked during ip_set_test, the following situations may occur: CPU0 CPU1 ip_rcv-> ip_rcv_finish-> ip_local_deliver-> nf_hook_slow-> iptable_filter_hook-> ipt_do_table-> set_match_v4-> ip_set_test-> list_set_destroy-> hash_net4_kadt-> set->data = NULL h = set->data .cidr = INIT_CIDR(h->nets[0].cidr[0], HOST_MASK) The set->data is empty, continuing to access set->data will result in a kernel NULL pointer. The call trace is as follows: [2350616.024418] Call trace: [2350616.024670] hash_net4_kadt+0x38/0x148 [ip_set_hash_net] [2350616.025147] ip_set_test+0xbc/0x230 [ip_set] [2350616.025549] set_match_v4+0xac/0xd0 [xt_set] [2350616.025951] ipt_do_table+0x32c/0x678 [ip_tables] [2350616.026391] iptable_filter_hook+0x30/0x40 [iptable_filter] [2350616.026905] nf_hook_slow+0x50/0x100 [2350616.027256] ip_local_deliver+0xd4/0xe8 [2350616.027616] ip_rcv_finish+0x90/0xb0 [2350616.027961] ip_rcv+0x50/0xb0 [2350616.028261] __netif_receive_skb_one_core+0x58/0x68 [2350616.028716] __netif_receive_skb+0x28/0x80 [2350616.029098] netif_receive_skb_internal+0x3c/0xa8 [2350616.029533] napi_gro_receive+0xf8/0x170 [2350616.029898] receive_buf+0xec/0xa08 [virtio_net] [2350616.030323] virtnet_poll+0x144/0x310 [virtio_net] [2350616.030761] net_rx_action+0x158/0x3a0 [2350616.031124] __do_softirq+0x11c/0x33c [2350616.031470] irq_exit+0x11c/0x128 [2350616.031793] __handle_domain_irq+0x6c/0xc0 [2350616.032172] gic_handle_irq+0x6c/0x170 [2350616.032528] el1_irq+0xb8/0x140 [2350616.032835] arch_cpu_idle+0x38/0x1c0 [2350616.033183] default_idle_call+0x24/0x58 [2350616.033549] do_idle+0x1a4/0x268 [2350616.033859] cpu_startup_entry+0x28/0x78 [2350616.034234] secondary_start_kernel+0x17c/0x1c8 Signed-off-by: Linkui Xiao <xiaolinkui@xxxxxxxxxx> --- net/netfilter/ipset/ip_set_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index 35d2f9c9ada0..46f4f47e29e4 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -747,7 +747,9 @@ ip_set_test(ip_set_id_t index, const struct sk_buff *skb, !(opt->family == set->family || set->family == NFPROTO_UNSPEC)) return 0; + ip_set_lock(set); ret = set->variant->kadt(set, skb, par, IPSET_TEST, opt); + ip_set_unlock(set); if (ret == -EAGAIN) { /* Type requests element to be completed */ -- 2.17.1