ipv6: sctp: fix lockdep splat in sctp_v6_get_dst()

commit 69ce6487dcd364245a3d26322fc8f4ffd1e8d947 upstream.

While cooking the sctp np->opt rcu fixes, I forgot to move
one rcu_read_unlock() after the added rcu_dereference() in
sctp_v6_get_dst()

This gave lockdep warnings reported by Dave Jones.

Fixes: c836a8ba9386 ("ipv6: sctp: add rcu protection around np->opt")
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 1f9a6f77980bf0d0911b803b54293a8252afd9d1..054c6a285661bbe25ee1b040dbfa2e2982e79ba1 100644 (file)
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -314,14 +314,13 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
                        }
                }
        }
-       rcu_read_unlock();
-
        if (baddr) {
                ipv6_addr_copy(&fl6->saddr, &baddr->v6.sin6_addr);
                fl6->fl6_sport = baddr->v6.sin6_port;
                final_p = fl6_update_dst(fl6, np->opt, &final);
                dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
        }
+       rcu_read_unlock();
 
 out:
        if (!IS_ERR(dst)) {