[VPP-1687] VPP crashes when using GSO with VXLAN

[vvalderrv]

bt

#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51

#1  0x00007ffff58b8801 in __GI_abort () at abort.c:79

#2  0x000055555555bffd in os_panic () at /home/sykazmi/vpp/src/vpp/vnet/main.c:355

#3  0x00007ffff5c9f0c9 in debugger () at /home/sykazmi/vpp/src/vppinfra/error.c:84

#4  0x00007ffff5c9f504 in _clib_error (how_to_die=2, function_name=0x0, line_number=0, 

    fmt=0x7ffff7680698 "%s:%d (%s) assertion `%s' fails")

    at /home/sykazmi/vpp/src/vppinfra/error.c:143

#5  0x00007ffff6b415eb in vnet_interface_output_node_inline_gso (vm=0x7fffb59f5900, 

    node=0x7fffb5b16240, frame=0x7fffb53fc4c0, vnm=0x7ffff7b5c0e0 <vnet_main>, hi=0x7fffb5a49770, 

    do_tx_offloads=0, do_segmentation=1) at /home/sykazmi/vpp/src/vnet/interface_output.c:678

#6  0x00007ffff6b41c93 in vnet_interface_output_node_inline (vm=0x7fffb59f5900, 

    node=0x7fffb5b16240, frame=0x7fffb53fc4c0, vnm=0x7ffff7b5c0e0 <vnet_main>, hi=0x7fffb5a49770, 

    do_tx_offloads=0) at /home/sykazmi/vpp/src/vnet/interface_output.c:857

#7  0x00007ffff6b41d4c in vnet_interface_output_node (vm=0x7fffb59f5900, node=0x7fffb5b16240, 

    frame=0x7fffb53fc4c0) at /home/sykazmi/vpp/src/vnet/interface_output.c:875

#8  0x00007ffff6229bf9 in dispatch_node (vm=0x7fffb59f5900, node=0x7fffb5b16240, 

    type=VLIB_NODE_TYPE_INTERNAL, dispatch_state=VLIB_NODE_STATE_POLLING, frame=0x7fffb53fc4c0, 

    last_time_stamp=955445360898132) at /home/sykazmi/vpp/src/vlib/main.c:1213

#9  0x00007ffff622a3d4 in dispatch_pending_node (vm=0x7fffb59f5900, pending_frame_index=7, 

    last_time_stamp=955445360898132) at /home/sykazmi/vpp/src/vlib/main.c:1381

#10 0x00007ffff622c18e in vlib_main_or_worker_loop (vm=0x7fffb59f5900, is_main=0)

    at /home/sykazmi/vpp/src/vlib/main.c:1824

#11 0x00007ffff622ca4c in vlib_worker_loop (vm=0x7fffb59f5900)

    at /home/sykazmi/vpp/src/vlib/main.c:1932

#12 0x00007ffff626f39a in vlib_worker_thread_fn (arg=0x7fffb4bdc1c0)

    at /home/sykazmi/vpp/src/vlib/threads.c:1744

#13 0x00007ffff5cc23ac in clib_calljmp ()

   from /home/sykazmi/vpp/build-root/install-vpp_debug-native/vpp/lib/libvppinfra.so.19.08

#14 0x00007ffdd3ffed10 in ?? ()

#15 0x00007ffff6269b20 in vlib_worker_thread_bootstrap_fn (arg=0x7fffb4bdc1c0)

    at /home/sykazmi/vpp/src/vlib/threads.c:596

Backtrace stopped: previous frame inner to this frame (corrupt stack?)