[PATCH 6.1.y 6.6.y] netfilter: nft_set_pipapo: restore cloned mapping table memcg accounting

[Karl Mehltretter <kmehltretter@gmail.com>]

The 6.1.y and 6.6.y backports of commit 69e687cea79f
("netfilter: nf_tables: missing objects with no memcg accounting")
changed the pipapo_clone() mapping-table allocation to
GFP_KERNEL_ACCOUNT.

Later stable backports of commit 07ace0bbe03b ("netfilter:
nft_set_pipapo: do not rely on ZERO_SIZE_PTR") rewrote this allocation
and changed the flag back to GFP_KERNEL. Upstream applied the
ZERO_SIZE_PTR change before the memcg accounting change and retains
GFP_KERNEL_ACCOUNT after both.

nft_pipapo_deactivate() clones a populated set before looking up an
element to delete. If the element is absent, priv->dirty remains false
and the clone is retained. Its mapping tables therefore remain allocated
without being charged to the requesting memory cgroup.

Restore GFP_KERNEL_ACCOUNT for the cloned mapping table.

For a 32,768-element two-field concatenation set, A/B tests on 6.1.186
and 6.6.155 measured exactly 524,288 additional bytes charged to the
memory cgroup after restoring the flag. An unmodified 6.12.107 control
already accounted the corresponding allocation and showed the same
accounting behavior.

Fixes: a4983e89e3b1 ("netfilter: nft_set_pipapo: do not rely on ZERO_SIZE_PTR")
Fixes: 32bad10de347 ("netfilter: nft_set_pipapo: do not rely on ZERO_SIZE_PTR")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
---
 net/netfilter/nft_set_pipapo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index 7c8d28a031ad..4c3bb5d61a3b 100644
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -1465,7 +1465,7 @@ static struct nft_pipapo_match *pipapo_clone(struct nft_pipapo_match *old)
 				goto out_mt;
 
 			dst->mt = kvmalloc_array(src->rules, sizeof(*src->mt),
-						 GFP_KERNEL);
+						 GFP_KERNEL_ACCOUNT);
 			if (!dst->mt)
 				goto out_mt;
 
-- 
2.39.5 (Apple Git-154)