netfilter: nf_tables: flush pending destroy work before netlink notifier

Destroy work waits for the RCU grace period then it releases the objects
with no mutex held. All releases objects follow this path for
transactions, therefore, order is guaranteed and references to top-level
objects in the hierarchy remain valid.

However, netlink notifier might interfer with pending destroy work.
rcu_barrier() is not correct because objects are not release via RCU
callback. Flush destroy work before releasing objects from netlink
notifier path.

Fixes: d4bc8271db21 ("netfilter: nf_tables: netlink notifier might race to release objects")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index a76a62ebe9c936b616d1643cf7a6458f842de01f..d299e7aa1b9658e80c0b836a9d9cb3247f1758c9 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -11073,7 +11073,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event,
        gc_seq = nft_gc_seq_begin(nft_net);
 
        if (!list_empty(&nf_tables_destroy_list))
-               rcu_barrier();
+               nf_tables_trans_destroy_flush_work();
 again:
        list_for_each_entry(table, &nft_net->tables, list) {
                if (nft_table_has_owner(table) &&