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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2025-05-12 13:28:44 +0300
committerPablo Neira Ayuso <pablo@netfilter.org>2025-05-23 14:57:12 +0300
commita1f1acb9c5db9b385c9b3eb1f27f897c06df49ae (patch)
treec84d694ad80f4fa33a898bf57f38cecaf1381fee /net/ipv6
parent22a9613de4c29d7d0770bfb8a5a9d73eb8df7dad (diff)
downloadlinux-a1f1acb9c5db9b385c9b3eb1f27f897c06df49ae.tar.xz
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 <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Valentin Schneider <vschneid@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/netfilter/ip6_tables.c2
-rw-r--r--net/ipv6/netfilter/nf_dup_ipv6.c6
2 files changed, 4 insertions, 4 deletions
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);
}