From: Sebastian Andrzej Siewior Date: Thu, 20 Jun 2024 13:21:57 +0000 (+0200) Subject: netfilter: br_netfilter: Use nested-BH locking for brnf_frag_data_storage. X-Git-Tag: nvme-6.11-2024-08-08~98^2~147^2~8 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=c67ef53a88db5bcc29a6da20dcbc09206d49d0a9;p=nvme.git netfilter: br_netfilter: Use nested-BH locking for brnf_frag_data_storage. brnf_frag_data_storage is a per-CPU variable and relies on disabled BH for its locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT this data structure requires explicit locking. Add a local_lock_t to the data structure and use local_lock_nested_bh() for locking. This change adds only lockdep coverage and does not alter the functional behaviour for !PREEMPT_RT. Cc: Florian Westphal Cc: Jozsef Kadlecsik Cc: Nikolay Aleksandrov Cc: Pablo Neira Ayuso Cc: Roopa Prabhu Cc: bridge@lists.linux.dev Cc: coreteam@netfilter.org Signed-off-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20240620132727.660738-8-bigeasy@linutronix.de Signed-off-by: Jakub Kicinski --- diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c index bf30c50b5689..3c9f6538990e 100644 --- a/net/bridge/br_netfilter_hooks.c +++ b/net/bridge/br_netfilter_hooks.c @@ -137,6 +137,7 @@ static inline bool is_pppoe_ipv6(const struct sk_buff *skb, #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN) struct brnf_frag_data { + local_lock_t bh_lock; char mac[NF_BRIDGE_MAX_MAC_HEADER_LENGTH]; u8 encap_size; u8 size; @@ -144,7 +145,9 @@ struct brnf_frag_data { __be16 vlan_proto; }; -static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage); +static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage) = { + .bh_lock = INIT_LOCAL_LOCK(bh_lock), +}; static void nf_bridge_info_free(struct sk_buff *skb) { @@ -850,6 +853,7 @@ static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff { struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb); unsigned int mtu, mtu_reserved; + int ret; mtu_reserved = nf_bridge_mtu_reduction(skb); mtu = skb->dev->mtu; @@ -882,6 +886,7 @@ static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff IPCB(skb)->frag_max_size = nf_bridge->frag_max_size; + local_lock_nested_bh(&brnf_frag_data_storage.bh_lock); data = this_cpu_ptr(&brnf_frag_data_storage); if (skb_vlan_tag_present(skb)) { @@ -897,7 +902,9 @@ static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff skb_copy_from_linear_data_offset(skb, -data->size, data->mac, data->size); - return br_nf_ip_fragment(net, sk, skb, br_nf_push_frag_xmit); + ret = br_nf_ip_fragment(net, sk, skb, br_nf_push_frag_xmit); + local_unlock_nested_bh(&brnf_frag_data_storage.bh_lock); + return ret; } if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) { @@ -909,6 +916,7 @@ static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size; + local_lock_nested_bh(&brnf_frag_data_storage.bh_lock); data = this_cpu_ptr(&brnf_frag_data_storage); data->encap_size = nf_bridge_encap_header_len(skb); data->size = ETH_HLEN + data->encap_size; @@ -916,8 +924,12 @@ static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff skb_copy_from_linear_data_offset(skb, -data->size, data->mac, data->size); - if (v6ops) - return v6ops->fragment(net, sk, skb, br_nf_push_frag_xmit); + if (v6ops) { + ret = v6ops->fragment(net, sk, skb, br_nf_push_frag_xmit); + local_unlock_nested_bh(&brnf_frag_data_storage.bh_lock); + return ret; + } + local_unlock_nested_bh(&brnf_frag_data_storage.bh_lock); kfree_skb(skb); return -EMSGSIZE;