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netfilter: br_netfilter: Use nested-BH locking for brnf_frag_data_storage.

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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 <fw@strlen.de>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: bridge@lists.linux.dev
Cc: coreteam@netfilter.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20240620132727.660738-8-bigeasy@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Sebastian Andrzej Siewior 2024-06-20 15:21:57 +02:00 committed by Jakub Kicinski
parent ebad6d0334
commit c67ef53a88
1 changed files with 16 additions and 4 deletions
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20
net/bridge/br_netfilter_hooks.c
View File

@ -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;