ng_ksocket & WITNESS

  I can easily reproduce this panic using today's CURRENT
and ng_ksocket and WITNESS turned on:

mutex Giant not owned at /usr/src/sys/netinet/udp_usrreq.c:734

#0  Debugger (msg=0x12 <Address 0x12 out of bounds>) at atomic.h:263
#1  0xc0563565 in panic (fmt=0xc0701209 "mutex %s not owned at %s:%d")
    at /usr/src/sys/kern/kern_shutdown.c:543
#2  0xc0559b4c in _mtx_assert (m=0xc0779320, what=-1056882688, 
    file=0xc070d665 "/usr/src/sys/netinet/udp_usrreq.c", line=734)
    at /usr/src/sys/kern/kern_mutex.c:747
#3  0xc060e47f in udp_output (inp=0xc17af21c, m=0xc172a500, addr=0x0, control=0x0, td=0xc15012c0)
    at /usr/src/sys/netinet/udp_usrreq.c:734
#4  0xc060f067 in udp_send (so=0x12, flags=0, m=0xc172a500, addr=0x12, control=0x12, td=0x12)
    at /usr/src/sys/netinet/udp_usrreq.c:1079
#5  0xc05a31ed in sosend (so=0xc17ae4f0, addr=0x0, uio=0x0, top=0xc172a500, control=0x0, flags=0, 
    td=0xc15012c0) at /usr/src/sys/kern/uipc_socket.c:788
#6  0xc05eb595 in ng_ksocket_rcvdata (hook=0xc19e9380, item=0xc17eb7c0)
    at /usr/src/sys/netgraph/ng_ksocket.c:917
#7  0xc05e4fe9 in ng_apply_item (node=0xc19d2800, item=0xc17eb7c0)
    at /usr/src/sys/netgraph/ng_base.c:2375
#8  0xc05e4b95 in ng_snd_item (item=0xc17eb7c0, queue=0) at /usr/src/sys/netgraph/ng_base.c:2264
#9  0xc1a01b09 in ?? ()
#10 0xc17eb7c0 in ?? ()

-- 
Totus tuus, Glebius.
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