1 files changed, 22 insertions, 9 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 4a8ad46397c0..ed00b233cee2 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -351,14 +351,14 @@ static void __inet_del_ifa(struct in_device *in_dev,
 {
 	struct in_ifaddr *promote = NULL;
 	struct in_ifaddr *ifa, *ifa1;
-	struct in_ifaddr *last_prim;
+	struct in_ifaddr __rcu **last_prim;
 	struct in_ifaddr *prev_prom = NULL;
 	int do_promote = IN_DEV_PROMOTE_SECONDARIES(in_dev);
 
 	ASSERT_RTNL();
 
 	ifa1 = rtnl_dereference(*ifap);
-	last_prim = rtnl_dereference(in_dev->ifa_list);
+	last_prim = ifap;
 	if (in_dev->dead)
 		goto no_promotions;
 
@@ -372,7 +372,7 @@ static void __inet_del_ifa(struct in_device *in_dev,
 		while ((ifa = rtnl_dereference(*ifap1)) != NULL) {
 			if (!(ifa->ifa_flags & IFA_F_SECONDARY) &&
 			    ifa1->ifa_scope <= ifa->ifa_scope)
-				last_prim = ifa;
+				last_prim = &ifa->ifa_next;
 
 			if (!(ifa->ifa_flags & IFA_F_SECONDARY) ||
 			    ifa1->ifa_mask != ifa->ifa_mask ||
@@ -436,9 +436,9 @@ no_promotions:
 
 			rcu_assign_pointer(prev_prom->ifa_next, next_sec);
 
-			last_sec = rtnl_dereference(last_prim->ifa_next);
+			last_sec = rtnl_dereference(*last_prim);
 			rcu_assign_pointer(promote->ifa_next, last_sec);
-			rcu_assign_pointer(last_prim->ifa_next, promote);
+			rcu_assign_pointer(*last_prim, promote);
 		}
 
 		promote->ifa_flags &= ~IFA_F_SECONDARY;
@@ -1798,6 +1798,21 @@ done:
 	return err;
 }
 
+/* Combine dev_addr_genid and dev_base_seq to detect changes.
+ */
+static u32 inet_base_seq(const struct net *net)
+{
+	u32 res = atomic_read(&net->ipv4.dev_addr_genid) +
+		  net->dev_base_seq;
+
+	/* Must not return 0 (see nl_dump_check_consistent()).
+	 * Chose a value far away from 0.
+	 */
+	if (!res)
+		res = 0x80000000;
+	return res;
+}
+
 static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	const struct nlmsghdr *nlh = cb->nlh;
@@ -1849,8 +1864,7 @@ static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
 		idx = 0;
 		head = &tgt_net->dev_index_head[h];
 		rcu_read_lock();
-		cb->seq = atomic_read(&tgt_net->ipv4.dev_addr_genid) ^
-			  tgt_net->dev_base_seq;
+		cb->seq = inet_base_seq(tgt_net);
 		hlist_for_each_entry_rcu(dev, head, index_hlist) {
 			if (idx < s_idx)
 				goto cont;
@@ -2249,8 +2263,7 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb,
 		idx = 0;
 		head = &net->dev_index_head[h];
 		rcu_read_lock();
-		cb->seq = atomic_read(&net->ipv4.dev_addr_genid) ^
-			  net->dev_base_seq;
+		cb->seq = inet_base_seq(net);
 		hlist_for_each_entry_rcu(dev, head, index_hlist) {
 			if (idx < s_idx)
 				goto cont;