panic: assertion: !IS_SERIALIZED((s)) in lwkt_serialize_enter

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

    I got this panic while messing around with the TAP interface on a
    recent HEAD.

    I'm not quite sure what the state of the TAP interfaces was when
    it occured.  I had three of them active, plus a bridge with one
    of them attached (but I don't think the bridge is related to the
    crash).

    In anycase, I've placed the kernel and vmcore in ~dillon/crash/*.17 on
    leaf.

						-Matt

#0  dumpsys () at ./machine/thread.h:83
#1  0xc0298f79 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:375
#2  0xc029923c in panic (fmt=0xc04f9f82 "from debugger")
    at /usr/src/sys/kern/kern_shutdown.c:800
#3  0xc016b9c9 in db_panic (addr=-1068883284, have_addr=0, count=-1, 
    modif=0xd27dfa78 "") at /usr/src/sys/ddb/db_command.c:447
#4  0xc016c034 in db_command_loop () at /usr/src/sys/ddb/db_command.c:343
#5  0xc016e5d0 in db_trap (type=3, code=0) at /usr/src/sys/ddb/db_trap.c:71
#6  0xc04a24b6 in kdb_trap (type=3, code=0, regs=0xd27dfb74)
    at /usr/src/sys/platform/pc32/i386/db_interface.c:148
#7  0xc04b36ea in trap (frame=0xd27dfb74)
    at /usr/src/sys/platform/pc32/i386/trap.c:832
#8  0xc04a31b7 in calltrap ()
    at /usr/src/sys/platform/pc32/i386/exception.s:785
#9  0xc04a22ac in Debugger (msg=0xc050989b "panic") at ./cpu/cpufunc.h:73
#10 0xc0299233 in panic (fmt=0xc04f7117 "assertion: %s in %s")
    at /usr/src/sys/kern/kern_shutdown.c:798
#11 0xc02a3869 in lwkt_serialize_enter (s=0xd27ff868)
    at /usr/src/sys/kern/lwkt_serialize.c:155
#12 0xc0305ad0 in ether_output (ifp=0xd27ff698, m=0xd6003400, dst=0xd27dfc60, 
    rt=0x0) at /usr/src/sys/net/if_ethersubr.c:329
#13 0xc032c83b in arprequest (ifp=0xd27ff698, sip=0xc2673688, tip=0xc2673688, 
    enaddr=0xc26983cc "") at /usr/src/sys/netinet/if_ether.c:366
#14 0xc032c8b2 in arp_ifinit (ifp=0xd27ff698, ifa=0xc26735e0)
    at /usr/src/sys/netinet/if_ether.c:957
#15 0xc0304e71 in ether_ioctl (ifp=0xd27ff698, command=-2145359604, 
    data=0xc26735e0 "\2046gÂ\2246g¤6gÂ")
    at /usr/src/sys/net/if_ethersubr.c:952
#16 0xc074463f in ?? ()
#17 0xc032e9a0 in in_ifinit (ifp=0xd27ff698, ia=0xd27ff698, sin=0xd621fc2c, 
    scrub=0) at /usr/src/sys/netinet/in.c:768
#18 0xc032f47e in in_control_internal (cmd=2151704858, data=0xd621fc1c "tap2", 
    ifp=0xd27ff698, td=0xd472a6f0) at /usr/src/sys/netinet/in.c:482
#19 0xc032fb9d in in_control_dispatch (nmsg=0xd621fae0)
    at /usr/src/sys/netinet/in.c:200
#20 0xc030ec01 in netmsg_service_loop (arg=0x0)
    at /usr/src/sys/net/netisr.c:247