[SCTP] ipv6: inconsistent lock state ipv6_add_addr/sctp_v6_copy_addrlist

lockdep found that dev->lock taken from softirq in ipv6_add_addr
is also taken in sctp_v6_copy_addrlist with softirqs enabled, so
lockup is possible.

Noticed-by: Simon Arlott <simon@arlott.org>
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 63fe1093b61635f06ecfc821e2c3caf6e68524eb..0b9c49b3a10000a07b391e164715cae8e322565f 100644 (file)
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -360,7 +360,7 @@ static void sctp_v6_copy_addrlist(struct list_head *addrlist,
                return;
        }
 
-       read_lock(&in6_dev->lock);
+       read_lock_bh(&in6_dev->lock);
        for (ifp = in6_dev->addr_list; ifp; ifp = ifp->if_next) {
                /* Add the address to the local list.  */
                addr = t_new(struct sctp_sockaddr_entry, GFP_ATOMIC);
@@ -374,7 +374,7 @@ static void sctp_v6_copy_addrlist(struct list_head *addrlist,
                }
        }
 
-       read_unlock(&in6_dev->lock);
+       read_unlock_bh(&in6_dev->lock);
        rcu_read_unlock();
 }