m_copydata panic in vkernel

[Matthew Dillon]

    While running stress2 using trevorjk's vkernel setup with the
    latest head as of last night (after my second round of pthread
    fixes for the vkernel) I got a mbuf panic:

    panic: m_copydata, negative off -1
    mp_lock = 00000001; cpuid = 1
    Trace beginning at frame 0x57a9ea04
    panic(57a9ea28,c,0,579218c0,57a9ea38) at 0x80bb436
    panic(823d90d,ffffffff,c,0,579218c0) at 0x80bb436
    m_copydata(0,ffffffff,1,59305dbc,0) at 0x80eacdc
    tcp_output(579218c0,59305d18,57a9eb44,59305d9c,59305d88) at 0x815e3bc
    tcp_input(59305d00,14,6,59305d00,584aae20) at 0x815d29a
    ip_reass(283a0150,14,0,0,0) at 0x8153362
    ip_input(59305d00,57a9ed60,8136b31,59305d18,1) at 0x8154a73
    ip_input(59305d18,1,8342c68,57a9ed84,8160775) at 0x8154aa7
    netmsg_service(59305d18,1,0,1,414003b8) at 0x8136b31
    tcpmsg_service_loop(0,0,0,0,0) at 0x8160775
    Debugger("panic")

    The vkernel is bring run on my 2xCPU test box, configured -n 2 -m 128m.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>