From 0b8d30c9a33bebe8fb8efda784cff05068d75901 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Fri, 22 Sep 2023 19:01:13 +0200 Subject: [PATCH] netfilter: nf_tables: defer gc run if previous batch is still pending commit 8e51830e29e12670b4c10df070a4ea4c9593e961 upstream. 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 Signed-off-by: Sasha Levin Gbp-Pq: Topic bugfix/all Gbp-Pq: Name netfilter-nf_tables-defer-gc-run-if-previous-batch-i.patch --- include/net/netfilter/nf_tables.h | 5 +++++ net/netfilter/nft_set_hash.c | 3 +++ net/netfilter/nft_set_rbtree.c | 3 +++ 3 files changed, 11 insertions(+) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 9182b583d42..bbe472c07d0 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -479,6 +479,11 @@ static inline void *nft_set_priv(const struct nft_set *set) return (void *)set->data; } +static inline bool nft_set_gc_is_pending(const struct nft_set *s) +{ + return refcount_read(&s->refs) != 1; +} + static inline struct nft_set *nft_set_container_of(const void *priv) { return (void *)priv - offsetof(struct nft_set, data); diff --git a/net/netfilter/nft_set_hash.c b/net/netfilter/nft_set_hash.c index 9cdf348b048..68a16ee37b3 100644 --- a/net/netfilter/nft_set_hash.c +++ b/net/netfilter/nft_set_hash.c @@ -312,6 +312,9 @@ static void nft_rhash_gc(struct work_struct *work) nft_net = net_generic(net, nf_tables_net_id); 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; diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index ed14849aa47..9b0bdd42161 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -613,6 +613,9 @@ static void nft_rbtree_gc(struct work_struct *work) nft_net = net_generic(net, nf_tables_net_id); 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; -- 2.30.2