ipv6: Use RCU in ip6_input()

Instead of grabbing rcu_read_lock() from ip6_input_finish(),
do it earlier in is caller, so that ip6_input() access
to dev_net() can be validated by LOCKDEP.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250205155120.1676781-13-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 70c0e16c0ae6837d1c64d0036829c8b61799578b..39da6a7ce5f1245145dd74d4ac4eae63dd970939 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -477,9 +477,7 @@ discard:
 static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
        skb_clear_delivery_time(skb);
-       rcu_read_lock();
        ip6_protocol_deliver_rcu(net, skb, 0, false);
-       rcu_read_unlock();
 
        return 0;
 }
@@ -487,9 +485,15 @@ static int ip6_input_finish(struct net *net, struct sock *sk, struct sk_buff *sk
 
 int ip6_input(struct sk_buff *skb)
 {
-       return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
-                      dev_net(skb->dev), NULL, skb, skb->dev, NULL,
-                      ip6_input_finish);
+       int res;
+
+       rcu_read_lock();
+       res = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
+                     dev_net_rcu(skb->dev), NULL, skb, skb->dev, NULL,
+                     ip6_input_finish);
+       rcu_read_unlock();
+
+       return res;
 }
 EXPORT_SYMBOL_GPL(ip6_input);