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 6.1-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-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4b94d86ba6d5707a73ab3cfa13917e8652ad6865
Author: Florian Westphal <fw@xxxxxxxxx>
Date: Fri Sep 22 18:30:23 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 2d501dd901521..12777a5b60cd0 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -581,6 +581,11 @@ 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 cef5df8460009..524763659f251 100644
--- a/net/netfilter/nft_set_hash.c
+++ b/net/netfilter/nft_set_hash.c
@@ -326,6 +326,9 @@ static void nft_rhash_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;
diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
index f9d4c8fcbbf82..c6435e7092319 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;
