From 8e51830e29e12670b4c10df070a4ea4c9593e961 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 22 Aug 2023 22:03:57 +0200 Subject: netfilter: nf_tables: defer gc run if previous batch is still pending Don't queue more gc work, else we may queue the same elements multiple times. If an element is flagged as dead, this can mean that either the previous gc request was invalidated/discarded by a transaction or that the previous request is still pending in the system work queue. The latter will happen if the gc interval is set to a very low value, e.g. 1ms, and system work queue is backlogged. The sets refcount is 1 if no previous gc requeusts are queued, so add a helper for this and skip gc run if old requests are pending. Add a helper for this and skip the gc run in this case. Fixes: f6c383b8c31a ("netfilter: nf_tables: adapt set backend to use GC transaction API") Signed-off-by: Florian Westphal Reviewed-by: Pablo Neira Ayuso --- net/netfilter/nft_set_rbtree.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/netfilter/nft_set_rbtree.c') diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index f9d4c8fcbbf8..c6435e709231 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -611,6 +611,9 @@ static void nft_rbtree_gc(struct work_struct *work) nft_net = nft_pernet(net); gc_seq = READ_ONCE(nft_net->gc_seq); + if (nft_set_gc_is_pending(set)) + goto done; + gc = nft_trans_gc_alloc(set, gc_seq, GFP_KERNEL); if (!gc) goto done; -- cgit