DragonFlyBSD

I think line 271 in sys/netinet/udp_usrreq.c is unwanted
if (&curthread->td_msgport != netisr_cpuport(0)) {
/* * This pr_ctloutput msg will be forwarded * to netisr0 to run; we can't do direct * detaching anymore.
*/
inp->inp_flags &= ~INP_DIRECT_DETACH;

because of lines 1648-- Here we can hit "has mcast options" panic if &curthread->td_msgport was netisr_cpuport(0)
if (inp->inp_flags & INP_DIRECT_DETACH) {
/* * Direct detaching is allowed
*/
KASSERT 0,
("in the wildcardhash"));
KASSERT(inp->inp_moptions NULL, ("has mcast options"));
udp_detach2(so);
return;
}

The patch removes 'if' statement, so no more fast detach for multicast udp.