tcp: ipv4: Pass lockdep expression to RCU lists

md5sig->head maybe traversed using hlist_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of socket lock.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.

Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index df1166b..52acf0b 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1019,7 +1019,8 @@ struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
        if (!md5sig)
                return NULL;
 
-       hlist_for_each_entry_rcu(key, &md5sig->head, node) {
+       hlist_for_each_entry_rcu(key, &md5sig->head, node,
+                                lockdep_sock_is_held(sk)) {
                if (key->family != family)
                        continue;
                if (key->l3index && key->l3index != l3index)
@@ -1064,7 +1065,8 @@ static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
        if (family == AF_INET6)
                size = sizeof(struct in6_addr);
 #endif
-       hlist_for_each_entry_rcu(key, &md5sig->head, node) {
+       hlist_for_each_entry_rcu(key, &md5sig->head, node,
+                                lockdep_sock_is_held(sk)) {
                if (key->family != family)
                        continue;
                if (key->l3index && key->l3index != l3index)