This is a note to let you know that I've just added the patch titled
netfilter: nf_tables: defer gc run if previous batch is still pending
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-nf_tables-defer-gc-run-if-previous-batch-i.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 39ff40482cf2bb0984686ed1f8d8414da1f0e394
Author: Florian Westphal <fw@xxxxxxxxx>
Date: Fri Sep 22 19:01:13 2023 +0200
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 <fw@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 9182b583d4297..bbe472c07d07e 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 9cdf348b048a4..68a16ee37b3d0 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 ed14849aa47f4..9b0bdd4216152 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;
