From: Li RongQing lirongqing@baidu.com
[ Upstream commit a9f5e78c403d2d62ade4f4c85040efc85f4049b8 ]
Check the result of dereferencing base_chain->stats, instead of result of this_cpu_ptr with NULL.
base_chain->stats maybe be changed to NULL when a chain is updated and a new NULL counter can be attached.
And we do not need to check returning of this_cpu_ptr since base_chain->stats is from percpu allocator if it is non-NULL, this_cpu_ptr returns a valid value.
And fix two sparse error by replacing rcu_access_pointer and rcu_dereference with READ_ONCE under rcu_read_lock.
Thanks for Eric's help to finish this patch.
Fixes: 009240940e84c1 ("netfilter: nf_tables: don't assume chain stats are set when jumplabel is set") Signed-off-by: Eric Dumazet eric.dumazet@gmail.com Signed-off-by: Zhang Yu zhangyu31@baidu.com Signed-off-by: Li RongQing lirongqing@baidu.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_tables_core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index a50500232b0a..7e8dae82ca52 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -98,21 +98,23 @@ static noinline void nft_update_chain_stats(const struct nft_chain *chain, const struct nft_pktinfo *pkt) { struct nft_base_chain *base_chain; + struct nft_stats __percpu *pstats; struct nft_stats *stats;
base_chain = nft_base_chain(chain); - if (!rcu_access_pointer(base_chain->stats)) - return;
- local_bh_disable(); - stats = this_cpu_ptr(rcu_dereference(base_chain->stats)); - if (stats) { + rcu_read_lock(); + pstats = READ_ONCE(base_chain->stats); + if (pstats) { + local_bh_disable(); + stats = this_cpu_ptr(pstats); u64_stats_update_begin(&stats->syncp); stats->pkts++; stats->bytes += pkt->skb->len; u64_stats_update_end(&stats->syncp); + local_bh_enable(); } - local_bh_enable(); + rcu_read_unlock(); }
struct nft_jumpstack {