This looks more useful:
hread 50 (Thread 0x7fff00868700 (LWP 18409)):
#0  0x00007ffff7bc1ad3 in futex_wait_cancelable (private=<optimised out>, expected=0, futex_word=0x55555a5de548)
    at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55555a5de550, cond=0x55555a5de520) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55555a5de520, mutex=0x55555a5de550) at pthread_cond_wait.c:655
#3  0x00007fffb57f54cb in __gthread_cond_wait (__mutex=<optimised out>, __cond=<optimised out>)
    at /home/nwani/m3/conda-bld/compilers_linux-64_1560109574129/work/.build/x86_64-conda_cos6-linux-gnu/build/build-cc-gcc-final/x86_64-conda_cos6-linux-gnu/libstdc++-v3/include/x86_64-conda_cos6-linux-gnu/bits/gthr-default.h:878
#4  std::condition_variable::wait (this=<optimised out>, __lock=...)
    at /home/nwani/m3/conda-bld/compilers_linux-64_1560109574129/work/.build/x86_64-conda_cos6-linux-gnu/src/gcc/libstdc++-v3/src/c++11/condition_variable.cc:53
#5  0x00007fff8cf9cb8b in torch::autograd::ReadyQueue::pop() () from /home/ian/anaconda3/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#6  0x00007fff8cfa1cd9 in torch::autograd::Engine::thread_main(std::shared_ptr<torch::autograd::GraphTask> const&) ()
   from /home/ian/anaconda3/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#7  0x00007fff8cf996a9 in torch::autograd::Engine::thread_init(int, std::shared_ptr<torch::autograd::ReadyQueue> const&, bool) ()
   from /home/ian/anaconda3/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#8  0x00007fff91ec451a in torch::autograd::python::PythonEngine::thread_init(int, std::shared_ptr<torch::autograd::ReadyQueue> const&, bool) ()
   from /home/ian/anaconda3/lib/python3.7/site-packages/torch/lib/libtorch_python.so
#9  0x00007fffb57f919d in std::execute_native_thread_routine (__p=0x55555a5aec80)
    at /home/nwani/m3/conda-bld/compilers_linux-64_1560109574129/work/.build/x86_64-conda_cos6-linux-gnu/src/gcc/libstdc++-v3/src/c++11/thread.cc:80

#10 0x00007ffff7bbb6db in start_thread (arg=0x7fff00868700) at pthread_create.c:463
#11 0x00007ffff78e471f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 49 (Thread 0x7fff00067700 (LWP 18408)):
#0  0x00007ffff78e60c7 in accept4 (fd=15, addr=..., addr_len=0x7fff00066df8, flags=524288) at ../sysdeps/unix/sysv/linux/accept4.c:32
#1  0x00007ffeeed009c6 in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#2  0x00007ffeeecf1f6d in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#3  0x00007ffeeed02a18 in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#4  0x00007ffff7bbb6db in start_thread (arg=0x7fff00067700) at pthread_create.c:463
#5  0x00007ffff78e471f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95