4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hangbin Liu <liuhangbin@xxxxxxxxx> [ Upstream commit 0e8411e426e277f55bd21e287ec89fab6f8eacae ] After route cache is flushed via ipv4_sysctl_rtcache_flush(), we forget to reset fnhe_mtu_locked in rt_bind_exception(). When pmtu is updated in __ip_rt_update_pmtu(), it will return directly since the pmtu is still locked. e.g. + ip netns exec client ping 10.10.1.1 -c 1 -s 1400 -M do PING 10.10.1.1 (10.10.1.1) 1400(1428) bytes of data. >From 10.10.0.254 icmp_seq=1 Frag needed and DF set (mtu = 0) Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/route.c | 1 + 1 file changed, 1 insertion(+) --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1376,6 +1376,7 @@ static bool rt_bind_exception(struct rta fnhe->fnhe_gw = 0; fnhe->fnhe_pmtu = 0; fnhe->fnhe_expires = 0; + fnhe->fnhe_mtu_locked = false; fnhe_flush_routes(fnhe); orig = NULL; }
