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Commit a778a15f authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
Browse files

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: default avatarLi Shuang <shuali@redhat.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Acked-by: default avatarJozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 49971b88

net/netfilter/ipset/ip_set_bitmap_gen.h

+1 −0
Original line number Diff line number Diff line
@@ -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) ||

net/netfilter/ipset/ip_set_core.c

+0 −2
Original line number Diff line number Diff line
@@ -1388,9 +1388,7 @@ ip_set_dump_start(struct sk_buff *skb, struct netlink_callback *cb) 
				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;

net/netfilter/ipset/ip_set_hash_gen.h

+1 −0
Original line number Diff line number Diff line
@@ -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",