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Subject: Test for cb809def1baaac68ab92
Author: syoshida@redhat.com

#syz test

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 2111af022d94..c6439e30e892 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1138,7 +1138,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 					fib6_set_expires(iter, rt->expires);
 					fib6_add_gc_list(iter);
 				}
-				if (!(rt->fib6_flags & (RTF_ADDRCONF | RTF_PREFIX_RT))) {
+				if (!(rt->fib6_flags & (RTF_ADDRCONF | RTF_PREFIX_RT)) &&
+				    !iter->fib6_nh->fib_nh_gw_family) {
 					iter->fib6_flags &= ~RTF_ADDRCONF;
 					iter->fib6_flags &= ~RTF_PREFIX_RT;
 				}