ndisc: ndisc_send_redirect() must use dev_get_by_index_rcu()

JIRA: https://issues.redhat.com/browse/RHEL-115578

commit 48145a5
Author: Eric Dumazet <edumazet@google.com>
Date:   Fri Feb 7 13:58:33 2025 +0000

    ndisc: ndisc_send_redirect() must use dev_get_by_index_rcu()

    ndisc_send_redirect() is called under RCU protection, not RTNL.

    It must use dev_get_by_index_rcu() instead of __dev_get_by_index()

    Fixes: 2f17bec ("vrf: check the original netdevice for generating redirect")
    Signed-off-by: Eric Dumazet <edumazet@google.com>
    Cc: Stephen Suryaputra <ssuryaextr@gmail.com>
    Reviewed-by: David Ahern <dsahern@kernel.org>
    Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
    Link: https://patch.msgid.link/20250207135841.1948589-2-edumazet@google.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: CKI Backport Bot <cki-ci-bot+cki-gitlab-backport-bot@redhat.com>

Author: CKI Backport Bot

net/ipv6/ndisc.c

@@ -1692,7 +1692,7 @@ void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
 	bool ret;
 
 	if (netif_is_l3_master(skb->dev)) {
-		dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
+		dev = dev_get_by_index_rcu(dev_net(skb->dev), IPCB(skb)->iif);
 		if (!dev)
 			return;
 	}