panic: mutex inp not owned at in_pcb.c:685

I'm getting one of these panics every time I cd into an amd mountpoint
on one of my machines with today's -current:

(kgdb) where
#0  doadump () at ../../../kern/kern_shutdown.c:240
#1  0xc04fd20f in boot (howto=260) at ../../../kern/kern_shutdown.c:372
#2  0xc04fd4c7 in panic () at ../../../kern/kern_shutdown.c:550
#3  0xc04f6248 in _mtx_assert (m=0xc1a238cc, what=0,
    file=0xc0662af6 "../../../netinet/in_pcb.c", line=685)
    at ../../../kern/kern_mutex.c:667
#4  0xc05659c7 in in_pcbdetach (inp=0xc1a23820)
    at ../../../netinet/in_pcb.c:685
#5  0xc057827b in tcp_twclose (tw=0xc1d79000, reuse=0)
    at ../../../netinet/tcp_subr.c:1725
#6  0xc05660a5 in in_pcblookup_local (pcbinfo=0xc06c36c0, laddr={s_addr = 0},
    lport_arg=3248633888, wild_okay=1) at ../../../netinet/in_pcb.c:1002
#7  0xc0565350 in in_pcbbind_setup (inp=0xc1a23680, nam=0xc19254a0,
    laddrp=0xc1a236b8, lportp=0xc1a2369a, td=0xc1cee640)
    at ../../../netinet/in_pcb.c:353
#8  0xc0565036 in in_pcbbind (inp=0xc1a23680, nam=0xc19254a0, td=0xc1cee640)
    at ../../../netinet/in_pcb.c:218
#9  0xc057a7c6 in tcp_usr_bind (so=0x0, nam=0xc19254a0, td=0xc1cee640)
    at ../../../netinet/tcp_usrreq.c:252
#10 0xc052c59e in sobind (so=0x0, nam=0xc19254a0, td=0xc1cee640)
    at ../../../kern/uipc_socket.c:230
#11 0xc052fb47 in kern_bind (td=0xc1cee640, fd=8, sa=0xc19254a0)
    at ../../../kern/uipc_syscalls.c:183
#12 0xc052faf3 in bind (td=0xc1cee640, uap=0xdce90d14)
    at ../../../kern/uipc_syscalls.c:163
#13 0xc06186cb in syscall (frame=
      {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = 8, tf_esi = -1077943876, tf_ebp = -1077943860, tf_isp = -588706444, tf_ebx = 1019, tf_edx = -1, tf_ecx = 48, tf_eax = 104, tf_trapno = 12, tf_err = 2, tf_eip = 671989471, tf_cs = 31, tf_eflags = 663, tf_esp = -1077943920, tf_ss = 47})
    at ../../../i386/i386/trap.c:1010
#14 0xc06096fd in Xint0x80_syscall () at {standard input}:136

-- 
	Dan Nelson
	dnelson_at_allantgroup.com