From: Pablo Neira Ayuso Date: Thu, 1 Feb 2018 18:49:00 +0100 Subject: [PATCH] netfilter: nft_flow_offload: wait for garbage collector to run after cleanup If netdevice goes down, then flowtable entries are scheduled to be removed. Wait for garbage collector to have a chance to run so it can delete them from the hashtable. The flush call might sleep, so hold the nfnl mutex from nft_flow_table_iterate() instead of rcu read side lock. The use of the nfnl mutex is also implicitly fixing races between updates via nfnetlink and netdevice event. Signed-off-by: Pablo Neira Ayuso --- --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4913,13 +4913,13 @@ void nft_flow_table_iterate(struct net * struct nft_flowtable *flowtable; const struct nft_table *table; - rcu_read_lock(); - list_for_each_entry_rcu(table, &net->nft.tables, list) { - list_for_each_entry_rcu(flowtable, &table->flowtables, list) { + nfnl_lock(NFNL_SUBSYS_NFTABLES); + list_for_each_entry(table, &net->nft.tables, list) { + list_for_each_entry(flowtable, &table->flowtables, list) { iter(&flowtable->data, data); } } - rcu_read_unlock(); + nfnl_unlock(NFNL_SUBSYS_NFTABLES); } EXPORT_SYMBOL_GPL(nft_flow_table_iterate); --- a/net/netfilter/nft_flow_offload.c +++ b/net/netfilter/nft_flow_offload.c @@ -208,6 +208,7 @@ static void nft_flow_offload_iterate_cle void *data) { nf_flow_table_iterate(flowtable, flow_offload_iterate_cleanup, data); + flush_delayed_work(&flowtable->gc_work); } static int flow_offload_netdev_event(struct notifier_block *this,