[PATCH net-next v4 06/15] xfrm: Use nested-BH locking for nat_keepalive_sk_ipv[46]
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2025-05-12 09:27:46
Also in:
linux-rt-devel
Subsystem:
networking [general], networking [ipsec], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Steffen Klassert, Herbert Xu, Linus Torvalds
nat_keepalive_sk_ipv[46] 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. Use sock_bh_locked which has a sock pointer and a local_lock_t. Use local_lock_nested_bh() for locking. This change adds only lockdep coverage and does not alter the functional behaviour for !PREEMPT_RT. Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- net/xfrm/xfrm_nat_keepalive.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/net/xfrm/xfrm_nat_keepalive.c b/net/xfrm/xfrm_nat_keepalive.c
index 82f0a301683f0..ebf95d48e86c1 100644
--- a/net/xfrm/xfrm_nat_keepalive.c
+++ b/net/xfrm/xfrm_nat_keepalive.c@@ -9,9 +9,13 @@ #include <net/ip6_checksum.h> #include <net/xfrm.h> -static DEFINE_PER_CPU(struct sock *, nat_keepalive_sk_ipv4); +static DEFINE_PER_CPU(struct sock_bh_locked, nat_keepalive_sk_ipv4) = { + .bh_lock = INIT_LOCAL_LOCK(bh_lock), +}; #if IS_ENABLED(CONFIG_IPV6) -static DEFINE_PER_CPU(struct sock *, nat_keepalive_sk_ipv6); +static DEFINE_PER_CPU(struct sock_bh_locked, nat_keepalive_sk_ipv6) = { + .bh_lock = INIT_LOCAL_LOCK(bh_lock), +}; #endif struct nat_keepalive {
@@ -56,10 +60,12 @@ static int nat_keepalive_send_ipv4(struct sk_buff *skb, skb_dst_set(skb, &rt->dst); - sk = *this_cpu_ptr(&nat_keepalive_sk_ipv4); + local_lock_nested_bh(&nat_keepalive_sk_ipv4.bh_lock); + sk = this_cpu_read(nat_keepalive_sk_ipv4.sock); sock_net_set(sk, net); err = ip_build_and_send_pkt(skb, sk, fl4.saddr, fl4.daddr, NULL, tos); sock_net_set(sk, &init_net); + local_unlock_nested_bh(&nat_keepalive_sk_ipv4.bh_lock); return err; }
@@ -89,15 +95,19 @@ static int nat_keepalive_send_ipv6(struct sk_buff *skb, fl6.fl6_sport = ka->encap_sport; fl6.fl6_dport = ka->encap_dport; - sk = *this_cpu_ptr(&nat_keepalive_sk_ipv6); + local_lock_nested_bh(&nat_keepalive_sk_ipv6.bh_lock); + sk = this_cpu_read(nat_keepalive_sk_ipv6.sock); sock_net_set(sk, net); dst = ipv6_stub->ipv6_dst_lookup_flow(net, sk, &fl6, NULL); - if (IS_ERR(dst)) + if (IS_ERR(dst)) { + local_unlock_nested_bh(&nat_keepalive_sk_ipv6.bh_lock); return PTR_ERR(dst); + } skb_dst_set(skb, dst); err = ipv6_stub->ip6_xmit(sk, skb, &fl6, skb->mark, NULL, 0, 0); sock_net_set(sk, &init_net); + local_unlock_nested_bh(&nat_keepalive_sk_ipv6.bh_lock); return err; } #endif
@@ -202,7 +212,7 @@ static void nat_keepalive_work(struct work_struct *work) (ctx.next_run - ctx.now) * HZ); } -static int nat_keepalive_sk_init(struct sock * __percpu *socks, +static int nat_keepalive_sk_init(struct sock_bh_locked __percpu *socks, unsigned short family) { struct sock *sk;
@@ -214,22 +224,22 @@ static int nat_keepalive_sk_init(struct sock * __percpu *socks, if (err < 0) goto err; - *per_cpu_ptr(socks, i) = sk; + per_cpu_ptr(socks, i)->sock = sk; } return 0; err: for_each_possible_cpu(i) - inet_ctl_sock_destroy(*per_cpu_ptr(socks, i)); + inet_ctl_sock_destroy(per_cpu_ptr(socks, i)->sock); return err; } -static void nat_keepalive_sk_fini(struct sock * __percpu *socks) +static void nat_keepalive_sk_fini(struct sock_bh_locked __percpu *socks) { int i; for_each_possible_cpu(i) - inet_ctl_sock_destroy(*per_cpu_ptr(socks, i)); + inet_ctl_sock_destroy(per_cpu_ptr(socks, i)->sock); } void xfrm_nat_keepalive_state_updated(struct xfrm_state *x)
--
2.49.0