4.16-stable review patch. If anyone has any objections, please let me know.
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From: Hangbin Liu liuhangbin@gmail.com
[ 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@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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; }