From: Sebastian Andrzej Siewior Date: Mon, 12 May 2025 10:28:44 +0000 (+0200) Subject: netfilter: nf_dup{4, 6}: Move duplication check to task_struct X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=a1f1acb9c5db9b385c9b3eb1f27f897c06df49ae;p=linux-2.6-microblaze.git netfilter: nf_dup{4, 6}: Move duplication check to task_struct nf_skb_duplicated 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. Due to the recursion involved, the simplest change is to make it a per-task variable. Move the per-CPU variable nf_skb_duplicated to task_struct and name it in_nf_duplicate. Add it to the existing bitfield so it doesn't use additional memory. Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman Cc: Valentin Schneider Acked-by: Peter Zijlstra (Intel) Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Pablo Neira Ayuso --- diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index 2b8aac2c70ad..892d12823ed4 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -497,17 +497,6 @@ struct nf_defrag_hook { extern const struct nf_defrag_hook __rcu *nf_defrag_v4_hook; extern const struct nf_defrag_hook __rcu *nf_defrag_v6_hook; -/* - * nf_skb_duplicated - TEE target has sent a packet - * - * When a xtables target sends a packet, the OUTPUT and POSTROUTING - * hooks are traversed again, i.e. nft and xtables are invoked recursively. - * - * This is used by xtables TEE target to prevent the duplicated skb from - * being duplicated again. - */ -DECLARE_PER_CPU(bool, nf_skb_duplicated); - /* * Contains bitmask of ctnetlink event subscribers, if any. * Can't be pernet due to NETLINK_LISTEN_ALL_NSID setsockopt flag. diff --git a/include/linux/sched.h b/include/linux/sched.h index f96ac1982893..52d9c52dc8f2 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1044,6 +1044,7 @@ struct task_struct { /* delay due to memory thrashing */ unsigned in_thrashing:1; #endif + unsigned in_nf_duplicate:1; #ifdef CONFIG_PREEMPT_RT struct netdev_xmit net_xmit; #endif diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 3d101613f27f..23c8deff8095 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -270,7 +270,7 @@ ipt_do_table(void *priv, * but it is no problem since absolute verdict is issued by these. */ if (static_key_false(&xt_tee_enabled)) - jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated); + jumpstack += private->stacksize * current->in_nf_duplicate; e = get_entry(table_base, private->hook_entry[hook]); diff --git a/net/ipv4/netfilter/nf_dup_ipv4.c b/net/ipv4/netfilter/nf_dup_ipv4.c index 25e1e8eb18dd..ed08fb78cfa8 100644 --- a/net/ipv4/netfilter/nf_dup_ipv4.c +++ b/net/ipv4/netfilter/nf_dup_ipv4.c @@ -54,7 +54,7 @@ void nf_dup_ipv4(struct net *net, struct sk_buff *skb, unsigned int hooknum, struct iphdr *iph; local_bh_disable(); - if (this_cpu_read(nf_skb_duplicated)) + if (current->in_nf_duplicate) goto out; /* * Copy the skb, and route the copy. Will later return %XT_CONTINUE for @@ -86,9 +86,9 @@ void nf_dup_ipv4(struct net *net, struct sk_buff *skb, unsigned int hooknum, --iph->ttl; if (nf_dup_ipv4_route(net, skb, gw, oif)) { - __this_cpu_write(nf_skb_duplicated, true); + current->in_nf_duplicate = true; ip_local_out(net, skb->sk, skb); - __this_cpu_write(nf_skb_duplicated, false); + current->in_nf_duplicate = false; } else { kfree_skb(skb); } diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 7d5602950ae7..d585ac3c1113 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -292,7 +292,7 @@ ip6t_do_table(void *priv, struct sk_buff *skb, * but it is no problem since absolute verdict is issued by these. */ if (static_key_false(&xt_tee_enabled)) - jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated); + jumpstack += private->stacksize * current->in_nf_duplicate; e = get_entry(table_base, private->hook_entry[hook]); diff --git a/net/ipv6/netfilter/nf_dup_ipv6.c b/net/ipv6/netfilter/nf_dup_ipv6.c index 0c39c77fe8a8..b903c62c00c9 100644 --- a/net/ipv6/netfilter/nf_dup_ipv6.c +++ b/net/ipv6/netfilter/nf_dup_ipv6.c @@ -48,7 +48,7 @@ void nf_dup_ipv6(struct net *net, struct sk_buff *skb, unsigned int hooknum, const struct in6_addr *gw, int oif) { local_bh_disable(); - if (this_cpu_read(nf_skb_duplicated)) + if (current->in_nf_duplicate) goto out; skb = pskb_copy(skb, GFP_ATOMIC); if (skb == NULL) @@ -64,9 +64,9 @@ void nf_dup_ipv6(struct net *net, struct sk_buff *skb, unsigned int hooknum, --iph->hop_limit; } if (nf_dup_ipv6_route(net, skb, gw, oif)) { - __this_cpu_write(nf_skb_duplicated, true); + current->in_nf_duplicate = true; ip6_local_out(net, skb->sk, skb); - __this_cpu_write(nf_skb_duplicated, false); + current->in_nf_duplicate = false; } else { kfree_skb(skb); } diff --git a/net/netfilter/core.c b/net/netfilter/core.c index b9f551f02c81..11a702065bab 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -31,9 +31,6 @@ const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly; EXPORT_SYMBOL_GPL(nf_ipv6_ops); -DEFINE_PER_CPU(bool, nf_skb_duplicated); -EXPORT_SYMBOL_GPL(nf_skb_duplicated); - #ifdef CONFIG_JUMP_LABEL struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; EXPORT_SYMBOL(nf_hooks_needed);