net: fix a lockdep rcu warning in __sk_dst_set()

__sk_dst_set() might be called while no state can be integrated in a
rcu_dereference_check() condition.

So use rcu_dereference_raw() to shutup lockdep warnings (if
CONFIG_PROVE_RCU is set)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 86a8ca177a2..4081db86a35 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1236,8 +1236,11 @@ __sk_dst_set(struct sock *sk, struct dst_entry *dst)
         struct dst_entry *old_dst;
 
         sk_tx_queue_clear(sk);
-        old_dst = rcu_dereference_check(sk->sk_dst_cache,
-                                        lockdep_is_held(&sk->sk_dst_lock));
+        /*
+         * This can be called while sk is owned by the caller only,
+         * with no state that can be checked in a rcu_dereference_check() cond
+         */
+        old_dst = rcu_dereference_raw(sk->sk_dst_cache);
         rcu_assign_pointer(sk->sk_dst_cache, dst);
         dst_release(old_dst);
 }