[PATCH 6.12.y 1/8] tcp: convert to dev_net_rcu()

20 Oct 2025

From: Eric Dumazet edumazet@google.com
[ Upstream commit e7b9ecce562ca6a1de32c56c597fa45e08c44ec0 ]
TCP uses of dev_net() are under RCU protection, change them
to dev_net_rcu() to get LOCKDEP support.
Signed-off-by: Eric Dumazet edumazet@google.com
Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com
Link: https://patch.msgid.link/20250301201424.2046477-4-edumazet@google.com
Signed-off-by: Jakub Kicinski kuba@kernel.org
Stable-dep-of: 833d4313bc1e ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin sashal@kernel.org
---
 include/net/inet6_hashtables.h |  2 +-
 include/net/inet_hashtables.h  |  2 +-
 net/ipv4/tcp_ipv4.c            | 12 ++++++------
 net/ipv4/tcp_metrics.c         |  6 +++---
 net/ipv6/tcp_ipv6.c            | 22 +++++++++++-----------
 5 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index 74dd90ff5f129..c32878c69179d 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -150,7 +150,7 @@ static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
    				      int iif, int sdif,
    				      bool *refcounted)
 {
-	struct net *net = dev_net(skb_dst(skb)->dev);
+	struct net *net = dev_net_rcu(skb_dst(skb)->dev);
    const struct ipv6hdr *ip6h = ipv6_hdr(skb);
    struct sock *sk;
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 5eea47f135a42..da818fb0205fe 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -492,7 +492,7 @@ static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
    				     const int sdif,
    				     bool *refcounted)
 {
-	struct net *net = dev_net(skb_dst(skb)->dev);
+	struct net *net = dev_net_rcu(skb_dst(skb)->dev);
    const struct iphdr *iph = ip_hdr(skb);
    struct sock *sk;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 824048679e1b8..d8976753d4e47 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -494,14 +494,14 @@ int tcp_v4_err(struct sk_buff *skb, u32 info)
 {
    const struct iphdr *iph = (const struct iphdr *)skb->data;
    struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
-	struct tcp_sock *tp;
+	struct net *net = dev_net_rcu(skb->dev);
    const int type = icmp_hdr(skb)->type;
    const int code = icmp_hdr(skb)->code;
-	struct sock *sk;
    struct request_sock *fastopen;
+	struct tcp_sock *tp;
    u32 seq, snd_una;
+	struct sock *sk;
    int err;
-	struct net *net = dev_net(skb->dev);
sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
    			       iph->daddr, th->dest, iph->saddr,
@@ -786,7 +786,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb,
    arg.iov[0].iov_base = (unsigned char *)&rep;
    arg.iov[0].iov_len  = sizeof(rep.th);
-	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
+	net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
/* Invalid TCP option size or twice included auth */
    if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
@@ -1965,7 +1965,7 @@ EXPORT_SYMBOL(tcp_v4_do_rcv);
int tcp_v4_early_demux(struct sk_buff *skb)
 {
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
    const struct iphdr *iph;
    const struct tcphdr *th;
    struct sock *sk;
@@ -2176,7 +2176,7 @@ static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
int tcp_v4_rcv(struct sk_buff *skb)
 {
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
    enum skb_drop_reason drop_reason;
    int sdif = inet_sdif(skb);
    int dif = inet_iif(skb);
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 95669935494ef..4251670e328c8 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -170,7 +170,7 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
    bool reclaim = false;
spin_lock_bh(&tcp_metrics_lock);
-	net = dev_net(dst->dev);
+	net = dev_net_rcu(dst->dev);
/* While waiting for the spin-lock the cache might have been populated
     * with this entry and so we have to check again.
@@ -273,7 +273,7 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
    	return NULL;
    }
-	net = dev_net(dst->dev);
+	net = dev_net_rcu(dst->dev);
    hash ^= net_hash_mix(net);
    hash = hash_32(hash, tcp_metrics_hash_log);
@@ -318,7 +318,7 @@ static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
    else
    	return NULL;
-	net = dev_net(dst->dev);
+	net = dev_net_rcu(dst->dev);
    hash ^= net_hash_mix(net);
    hash = hash_32(hash, tcp_metrics_hash_log);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 882ce5444572e..06edfe0b2db90 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -376,7 +376,7 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 {
    const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
    const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
    struct request_sock *fastopen;
    struct ipv6_pinfo *np;
    struct tcp_sock *tp;
@@ -864,16 +864,16 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
    			 int oif, int rst, u8 tclass, __be32 label,
    			 u32 priority, u32 txhash, struct tcp_key *key)
 {
-	const struct tcphdr *th = tcp_hdr(skb);
-	struct tcphdr *t1;
-	struct sk_buff *buff;
-	struct flowi6 fl6;
-	struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
-	struct sock *ctl_sk = net->ipv6.tcp_sk;
+	struct net *net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
    unsigned int tot_len = sizeof(struct tcphdr);
+	struct sock *ctl_sk = net->ipv6.tcp_sk;
+	const struct tcphdr *th = tcp_hdr(skb);
    __be32 mrst = 0, *topt;
    struct dst_entry *dst;
-	__u32 mark = 0;
+	struct sk_buff *buff;
+	struct tcphdr *t1;
+	struct flowi6 fl6;
+	u32 mark = 0;
if (tsecr)
    	tot_len += TCPOLEN_TSTAMP_ALIGNED;
@@ -1036,7 +1036,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb,
    if (!sk && !ipv6_unicast_destination(skb))
    	return;
-	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
+	net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
    /* Invalid TCP option size or twice included auth */
    if (tcp_parse_auth_options(th, &md5_hash_location, &aoh))
    	return;
@@ -1739,6 +1739,7 @@ static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 {
+	struct net *net = dev_net_rcu(skb->dev);
    enum skb_drop_reason drop_reason;
    int sdif = inet6_sdif(skb);
    int dif = inet6_iif(skb);
@@ -1748,7 +1749,6 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
    bool refcounted;
    int ret;
    u32 isn;
-	struct net *net = dev_net(skb->dev);
drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
    if (skb->pkt_type != PACKET_HOST)
@@ -1999,7 +1999,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
void tcp_v6_early_demux(struct sk_buff *skb)
 {
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
    const struct ipv6hdr *hdr;
    const struct tcphdr *th;
    struct sock *sk;
-- 
2.51.0



    

2025

2024

2023

2022

2021

2020

2019

2018

2017

[PATCH 6.12.y 1/8] tcp: convert to dev_net_rcu()