From: Eric Dumazet Date: Fri, 5 Sep 2025 16:58:07 +0000 (+0000) Subject: ipv6: snmp: do not track per idev ICMP6_MIB_RATELIMITHOST X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2fab94bcf313480336b0a41eb45a24ffd5087490;p=thirdparty%2Fkernel%2Fstable.git ipv6: snmp: do not track per idev ICMP6_MIB_RATELIMITHOST Blamed commit added a critical false sharing on a single atomic_long_t under DOS, like receiving UDP packets to closed ports. Per netns ICMP6_MIB_RATELIMITHOST tracking uses per-cpu storage and is enough, we do not need per-device and slow tracking. Fixes: d0941130c9351 ("icmp: Add counters for rate limits") Signed-off-by: Eric Dumazet Cc: Jamie Bainbridge Cc: Abhishek Rawal Link: https://patch.msgid.link/20250905165813.1470708-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 95cdd4cacb004..56c974cf75d15 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -230,8 +230,7 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, } rcu_read_unlock(); if (!res) - __ICMP6_INC_STATS(net, ip6_dst_idev(dst), - ICMP6_MIB_RATELIMITHOST); + __ICMP6_INC_STATS(net, NULL, ICMP6_MIB_RATELIMITHOST); else icmp_global_consume(net); dst_release(dst); diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c index 92ed04729c2f5..73296f38c2520 100644 --- a/net/ipv6/proc.c +++ b/net/ipv6/proc.c @@ -94,6 +94,7 @@ static const struct snmp_mib snmp6_icmp6_list[] = { SNMP_MIB_ITEM("Icmp6OutMsgs", ICMP6_MIB_OUTMSGS), SNMP_MIB_ITEM("Icmp6OutErrors", ICMP6_MIB_OUTERRORS), SNMP_MIB_ITEM("Icmp6InCsumErrors", ICMP6_MIB_CSUMERRORS), +/* ICMP6_MIB_RATELIMITHOST needs to be last, see snmp6_dev_seq_show(). */ SNMP_MIB_ITEM("Icmp6OutRateLimitHost", ICMP6_MIB_RATELIMITHOST), }; @@ -242,8 +243,11 @@ static int snmp6_dev_seq_show(struct seq_file *seq, void *v) snmp6_ipstats_list, ARRAY_SIZE(snmp6_ipstats_list), offsetof(struct ipstats_mib, syncp)); + + /* Per idev icmp stats do not have ICMP6_MIB_RATELIMITHOST */ snmp6_seq_show_item(seq, NULL, idev->stats.icmpv6dev->mibs, - snmp6_icmp6_list, ARRAY_SIZE(snmp6_icmp6_list)); + snmp6_icmp6_list, ARRAY_SIZE(snmp6_icmp6_list) - 1); + snmp6_seq_show_icmpv6msg(seq, idev->stats.icmpv6msgdev->mibs); return 0; }