Program received signal SIGSEGV, Segmentation fault.

(gdb) bt
#0  0x0000000000505e69 in boost::asio::detail::epoll_reactor::start_op (this=0x7fffd4002bf0, op_type=1, descriptor=39, 
    descriptor_data=@0x7fffd4003920: 0x0, op=0x7fffc8002940, allow_speculative=false)
    at /usr/include/boost/asio/detail/impl/epoll_reactor.ipp:217
#1  0x00000000005086e2 in boost::asio::detail::reactive_descriptor_service::start_op (this=0x7fffd40039d8, impl=..., op_type=1, 
    op=0x7fffc8002940, is_non_blocking=false, noop=false)
    at /usr/include/boost/asio/detail/impl/reactive_descriptor_service.ipp:189
#2  0x000000000050b877 in boost::asio::detail::reactive_descriptor_service::async_write_some<boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> > > (this=0x7fffd40039d8, impl=..., handler=...)
    at /usr/include/boost/asio/detail/reactive_descriptor_service.hpp:221
#3  0x000000000050ae03 in boost::asio::posix::stream_descriptor_service::async_write_some<boost::asio::null_buffers, boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> > > (this=0x7fffd40039b0, impl=..., buffers=..., handler=...)
    at /usr/include/boost/asio/posix/stream_descriptor_service.hpp:205
#4  0x0000000000509fe5 in boost::asio::posix::basic_stream_descriptor<boost::asio::posix::stream_descriptor_service>::async_write_some<boost::asio::null_buffers, boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> > > (this=0x7fffd4003910, 
    buffers=..., handler=...) at /usr/include/boost/asio/posix/basic_stream_descriptor.hpp:235
#5  0x00000000004fe402 in eve::USBDeviceProxy::Impl::schedule_async_write (this=0x7fffd4003870) at usbdevice_proxy.cpp:513
#6  0x00000000004fe5d7 in eve::USBDeviceProxy::Impl::do_write (this=0x7fffd4003870, ec=...) at usbdevice_proxy.cpp:551
#7  0x000000000050ce18 in boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>::operator() (
    this=0x7fffe55df9e0, p=0x7fffd4003870, a1=...) at /usr/include/boost/bind/mem_fn_template.hpp:165
#8  0x000000000050ccf7 in boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()>::operator()<boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::system::error_code const&, unsigned long const&> > (this=0x7fffe55df9f0, f=..., a=...) at /usr/include/boost/bind/bind.hpp:313
#9  0x000000000050cc34 in boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> >::operator()<boost::system::error_code, unsigned long> (this=0x7fffe55df9e0, a1=..., a2=@0x7fffe55dfa08: 0) at /usr/include/boost/bind/bind_template.hpp:102
#10 0x000000000050cbe5 in boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> >, boost::system::error_code, unsigned long>::operator() (this=0x7fffe55df9e0) at /usr/include/boost/asio/detail/bind_handler.hpp:118
#11 0x000000000050ca8a in boost::asio::asio_handler_invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> >, boost::system::error_code, unsigned long> > (function=...)
    at /usr/include/boost/asio/handler_invoke_hook.hpp:64
#12 0x000000000050c944 in boost_asio_handler_invoke_helpers::invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::---Type <return> to continue, or q <return> to quit---
_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> >, boost::system::error_code, unsigned long>, boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> > > (function=..., context=...) at /usr/include/boost/asio/detail/handler_invoke_helpers.hpp:39
#13 0x000000000050c51a in boost::asio::detail::reactive_null_buffers_op<boost::_bi::bind_t<void, boost::_mfi::mf1<void, eve::USBDeviceProxy::Impl, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<eve::USBDeviceProxy::Impl*>, boost::arg<1> (*)()> > >::do_complete (owner=0x7fffd40029e0, base=0x7fffc8002940)
    at /usr/include/boost/asio/detail/reactive_null_buffers_op.hpp:75
#14 0x0000000000504f30 in boost::asio::detail::task_io_service_operation::complete (this=0x7fffc8002940, owner=..., ec=..., 
    bytes_transferred=0) at /usr/include/boost/asio/detail/task_io_service_operation.hpp:37
#15 0x0000000000506b29 in boost::asio::detail::epoll_reactor::descriptor_state::do_complete (owner=0x7fffd40029e0, 
    base=0x7fffd4002b00, ec=..., bytes_transferred=24) at /usr/include/boost/asio/detail/impl/epoll_reactor.ipp:624
#16 0x0000000000504f30 in boost::asio::detail::task_io_service_operation::complete (this=0x7fffd4002b00, owner=..., ec=..., 
    bytes_transferred=24) at /usr/include/boost/asio/detail/task_io_service_operation.hpp:37
#17 0x00000000005075c4 in boost::asio::detail::task_io_service::do_run_one (this=0x7fffd40029e0, lock=..., this_thread=..., 
    private_op_queue=..., ec=...) at /usr/include/boost/asio/detail/impl/task_io_service.ipp:369
#18 0x0000000000507061 in boost::asio::detail::task_io_service::run (this=0x7fffd40029e0, ec=...)
    at /usr/include/boost/asio/detail/impl/task_io_service.ipp:146
#19 0x00000000005079a3 in boost::asio::io_service::run (this=0x7fffd40038e8) at /usr/include/boost/asio/impl/io_service.ipp:59
#20 0x00000000004fe2c1 in eve::USBDeviceProxy::Impl::do_run (this=0x7fffd4003870) at usbdevice_proxy.cpp:495
#21 0x000000000050d421 in boost::_mfi::mf0<void, eve::USBDeviceProxy::Impl>::operator() (this=0x7fffd4004b88, p=0x7fffd4003870)
    at /usr/include/boost/bind/mem_fn_template.hpp:49
#22 0x000000000050d3a2 in boost::_bi::list1<boost::_bi::value<eve::USBDeviceProxy::Impl*> >::operator()<boost::_mfi::mf0<void, eve::USBDeviceProxy::Impl>, boost::_bi::list0> (this=0x7fffd4004b98, f=..., a=...) at /usr/include/boost/bind/bind.hpp:253
#23 0x000000000050d347 in boost::_bi::bind_t<void, boost::_mfi::mf0<void, eve::USBDeviceProxy::Impl>, boost::_bi::list1<boost::_bi::value<eve::USBDeviceProxy::Impl*> > >::operator() (this=0x7fffd4004b88) at /usr/include/boost/bind/bind_template.hpp:20
#24 0x000000000050d21a in boost::detail::thread_data<boost::_bi::bind_t<void, boost::_mfi::mf0<void, eve::USBDeviceProxy::Impl>, boost::_bi::list1<boost::_bi::value<eve::USBDeviceProxy::Impl*> > > >::run (this=0x7fffd4004a00)
    at /usr/include/boost/thread/detail/thread.hpp:62
#25 0x00007ffff72f66e9 in ?? () from /usr/lib/libboost_thread.so.1.49.0
#26 0x00007ffff770ff8e in start_thread (arg=0x7fffe55e0700) at pthread_create.c:311
#27 0x00007ffff659be1d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113


void epoll_reactor::start_op(int op_type, socket_type descriptor,
    epoll_reactor::per_descriptor_data& descriptor_data,
    reactor_op* op, bool allow_speculative)
{
  if (!descriptor_data)
  {
    op->ec_ = boost::asio::error::bad_descriptor;
    post_immediate_completion(op);
    return;
  }

  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);

  if (descriptor_data->shutdown_) // segfault, line 217