From a778a15fa5cf5f632cd55845f548189a29e9b57b Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 30 Nov 2017 21:08:05 +0100 Subject: [PATCH] netfilter: ipset: add resched points during set listing When sets are extremely large we can get softlockup during ipset -L. We could fix this by adding cond_resched_rcu() at the right location during iteration, but this only works if RCU nesting depth is 1. At this time entire variant->list() is called under under rcu_read_lock_bh. This used to be a read_lock_bh() but as rcu doesn't really lock anything, it does not appear to be needed, so remove it (ipset increments set reference count before this, so a set deletion should not be possible). Reported-by: Li Shuang Signed-off-by: Florian Westphal Acked-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso --- net/netfilter/ipset/ip_set_bitmap_gen.h | 1 + net/netfilter/ipset/ip_set_core.c | 2 -- net/netfilter/ipset/ip_set_hash_gen.h | 1 + 3 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/ipset/ip_set_bitmap_gen.h b/net/netfilter/ipset/ip_set_bitmap_gen.h index 5ca18f0..8afe882 100644 --- a/net/netfilter/ipset/ip_set_bitmap_gen.h +++ b/net/netfilter/ipset/ip_set_bitmap_gen.h @@ -227,6 +227,7 @@ mtype_list(const struct ip_set *set, rcu_read_lock(); for (; cb->args[IPSET_CB_ARG0] < map->elements; cb->args[IPSET_CB_ARG0]++) { + cond_resched_rcu(); id = cb->args[IPSET_CB_ARG0]; x = get_ext(set, map, id); if (!test_bit(id, map->members) || diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index 1f3c03b..89b4445 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -1388,9 +1388,7 @@ dump_last: set->variant->uref(set, cb, true); /* fall through */ default: - rcu_read_lock_bh(); ret = set->variant->list(set, skb, cb); - rcu_read_unlock_bh(); if (!cb->args[IPSET_CB_ARG0]) /* Set is done, proceed with next one */ goto next_set; diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h index efffc8e..8ef079d 100644 --- a/net/netfilter/ipset/ip_set_hash_gen.h +++ b/net/netfilter/ipset/ip_set_hash_gen.h @@ -1143,6 +1143,7 @@ mtype_list(const struct ip_set *set, rcu_read_lock(); for (; cb->args[IPSET_CB_ARG0] < jhash_size(t->htable_bits); cb->args[IPSET_CB_ARG0]++) { + cond_resched_rcu(); incomplete = skb_tail_pointer(skb); n = rcu_dereference(hbucket(t, cb->args[IPSET_CB_ARG0])); pr_debug("cb->arg bucket: %lu, t %p n %p\n", -- 2.7.4