diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 61f26851655ccd23200278d34ceda44351da1c17..a57d3d17a6204c722fbb3ae6aea25460c44cbc34 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2455,7 +2455,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 			if (in6_dev->cnf.optimistic_dad &&
 			    !net->ipv6.devconf_all->forwarding && sllao)
-				addr_flags = IFA_F_OPTIMISTIC;
+				addr_flags |= IFA_F_OPTIMISTIC;
 #endif
 
 			/* Do not allow to create too much of autoconfigured