If netfilter changes the packet mark, the packet is rerouted. The
ip_route_me_harder family of functions fails to use the right sk, opting
to instead use skb->sk, resulting in a routing loop when used with
tunnels. Fixing this inside of the compat layer with skb_orphan would
work but would cause other problems, by disabling TSQ, so instead we
warn if the calling kernel hasn't yet backported the fix for this.
Reported-by: Chen Minqiang <ptpt52@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
85b12548cd