hang

hang

warning: Target and debugger are in different PID namespaces; thread lists and other data are likely unreliable
0x00007f44580af98d in pthread_join (threadid=139928609789696, thread_return=0x0) at pthread_join.c:90
90      pthread_join.c: No such file or directory.
(gdb) bt
#0  0x00007f44580af98d in pthread_join (threadid=139928609789696, thread_return=0x0) at pthread_join.c:90
#1  0x00007f4450b1fb97 in std::thread::join() () from target:/usr/lib/x86_64-linux-gnu/libstdc++.so.6
#2  0x00007f43f7a2f997 in mxnet::engine::ThreadPool::~ThreadPool (this=0x1af15540, __in_chrg=<optimized out>) at src/engine/./thread_pool.h:84
#3  std::default_delete<mxnet::engine::ThreadPool>::operator() (this=<optimized out>, __ptr=0x1af15540) at /usr/include/c++/5/bits/unique_ptr.h:76
#4  std::unique_ptr<mxnet::engine::ThreadPool, std::default_delete<mxnet::engine::ThreadPool> >::~unique_ptr (this=0x19516fe8, __in_chrg=<optimized out>)
    at /usr/include/c++/5/bits/unique_ptr.h:236
#5  mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0>::~ThreadWorkerBlock (this=0x19516f20, __in_chrg=<optimized out>)
    at src/engine/threaded_engine_perdevice.cc:204
#6  std::_Sp_counted_ptr<mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0>*, (__gnu_cxx::_Lock_policy)2>::_M_dispose (this=<optimized out>)
    at /usr/include/c++/5/bits/shared_ptr_base.h:374
#7  0x00007f43f4cf1037 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x19ce5ad0) at /usr/include/c++/5/bits/shared_ptr_base.h:150
#8  0x00007f43f7a2cf2b in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=<optimized out>, __in_chrg=<optimized out>)
    at /usr/include/c++/5/bits/shared_ptr_base.h:659
#9  std::__shared_ptr<mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0>, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=<optimized out>,
    __in_chrg=<optimized out>) at /usr/include/c++/5/bits/shared_ptr_base.h:925
#10 std::__shared_ptr<mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0>, (__gnu_cxx::_Lock_policy)2>::operator=(std::__shared_ptr<mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0>, (__gnu_cxx::_Lock_policy)2>&&) (__r=<optimized out>, this=<synthetic pointer>)
    at /usr/include/c++/5/bits/shared_ptr_base.h:1000
#11 std::shared_ptr<mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0> >::operator=(std::shared_ptr<mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0> >&&) (__r=<optimized out>, this=<synthetic pointer>) at /usr/include/c++/5/bits/shared_ptr.h:294
#12 mxnet::common::LazyAllocArray<mxnet::engine::ThreadedEnginePerDevice::ThreadWorkerBlock<(dmlc::ConcurrentQueueType)0> >::Clear (this=this@entry=0x30d6418)
    at src/engine/../common/lazy_alloc_array.h:149
#13 0x00007f43f7a2ea51 in mxnet::engine::ThreadedEnginePerDevice::StopNoWait (this=0x30d61f0) at src/engine/threaded_engine_perdevice.cc:79
#14 mxnet::engine::ThreadedEnginePerDevice::~ThreadedEnginePerDevice (this=0x30d61f0, __in_chrg=<optimized out>) at src/engine/threaded_engine_perdevice.cc:74
#15 0x00007f43f7a2f4b9 in mxnet::engine::ThreadedEnginePerDevice::~ThreadedEnginePerDevice (this=0x30d61f0, __in_chrg=<optimized out>) at src/engine/threaded_engine_perdevice.cc:75
#16 0x00007f43f7a215f2 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x1b54240) at /usr/include/c++/5/bits/shared_ptr_base.h:150
#17 std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=<optimized out>, __in_chrg=<optimized out>) at /usr/include/c++/5/bits/shared_ptr_base.h:659
#18 std::__shared_ptr<mxnet::Engine, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=<optimized out>, __in_chrg=<optimized out>) at /usr/include/c++/5/bits/shared_ptr_base.h:925
#19 std::shared_ptr<mxnet::Engine>::~shared_ptr (this=<optimized out>, __in_chrg=<optimized out>) at /usr/include/c++/5/bits/shared_ptr.h:93
#20 0x00007f4457d16ff8 in __run_exit_handlers (status=0, listp=0x7f44580a15f8 <__exit_funcs>, run_list_atexit=run_list_atexit@entry=true) at exit.c:82
#21 0x00007f4457d17045 in __GI_exit (status=<optimized out>) at exit.c:104
#22 0x000000000060db0f in Py_Exit ()
#23 0x000000000060dbfa in ?? ()
#24 0x000000000060dc66 in PyErr_PrintEx ()
#25 0x000000000060ef29 in PyRun_SimpleFileExFlags ()
#26 0x000000000063fb26 in Py_Main ()
#27 0x00000000004cfeb1 in main ()

what is the thread it's trying to join doing?