diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 3dfc50cd86d682fc266072e237cac75f0e7e19ca..c57efd5c5b387e17c7e99835f47b7fcb84e9acb5 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1148,7 +1148,8 @@ check_cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long *expires)
 	list_for_each_entry(ifa, &idev->addr_list, if_list) {
 		if (ifa == ifp)
 			continue;
-		if (!ipv6_prefix_equal(&ifa->addr, &ifp->addr,
+		if (ifa->prefix_len != ifp->prefix_len ||
+		    !ipv6_prefix_equal(&ifa->addr, &ifp->addr,
 				       ifp->prefix_len))
 			continue;
 		if (ifa->flags & (IFA_F_PERMANENT | IFA_F_NOPREFIXROUTE))