It still failed with 1.6.0 - similar stack trace:
#0  0x00007ffe767b7b44 in clock_gettime ()
#1  0x00007f5c2ea25056 in __GI___clock_gettime (clock_id=4, tp=0x7ffe7663c3a0) at ../sysdeps/unix/clock_gettime.c:115
#2  0x00007f59ee03370e in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#3  0x00007f59ee10c837 in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#4  0x00007f59ee12e7a9 in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#5  0x00007f59ee008d88 in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#6  0x00007f59edf0d612 in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#7  0x00007f59edf0fdcf in ?? () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#8  0x00007f59ee0b3cb5 in cuMemcpyDtoHAsync_v2 () from /usr/lib/x86_64-linux-gnu/libcuda.so.1
#9  0x00007f5c25ac795f in ?? () from /opt/conda/lib/python3.7/site-packages/torch/lib/libcudart-1b201d85.so.10.1
#10 0x00007f5c25aa3b13 in ?? () from /opt/conda/lib/python3.7/site-packages/torch/lib/libcudart-1b201d85.so.10.1
#11 0x00007f5c25ae3118 in cudaMemcpyAsync () from /opt/conda/lib/python3.7/site-packages/torch/lib/libcudart-1b201d85.so.10.1
#12 0x00007f5bc071918f in at::native::_local_scalar_dense_cuda(at::Tensor const&)::{lambda()#1}::operator()() const ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cuda.so
#13 0x00007f5bc071ac27 in at::native::_local_scalar_dense_cuda(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cuda.so
#14 0x00007f5bbf9b24c8 in at::CUDAType::_local_scalar_dense(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cuda.so
#15 0x00007f5bbf9dc7ad in c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoRuntimeFunctor_<c10::Scalar (*)(at::Tensor const&), c10::Scalar, c10::guts::typelist::typelist<at::Tensor const&> >, c10::Scalar (at::Tensor const&)>::call(c10::OperatorKernel*, at::Tensor const&) () from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cuda.so
#16 0x00007f5bf306e90d in at::_local_scalar_dense(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#17 0x00007f5bf4cc602c in torch::autograd::VariableType::_local_scalar_dense(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#18 0x00007f5bf2ff437d in c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoRuntimeFunctor_<c10::Scalar (*)(at::Tensor const&), c10::Scalar, c10::guts::typelist::typelist<at::Tensor const&> >, c10::Scalar (at::Tensor const&)>::call(c10::OperatorKernel*, at::Tensor const&) () from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#19 0x00007f5bf306e90d in at::_local_scalar_dense(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#20 0x00007f5bf2cf5b5b in at::native::item(at::Tensor const&) () from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#21 0x00007f5bf317e6b8 in at::TypeDefault::item(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#22 0x00007f5bf4d0d1b9 in torch::autograd::VariableType::item(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#23 0x00007f5bf2ff437d in c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoRuntimeFunctor_<c10::Scalar (*)(at::Tensor const&), c10::Scalar, c10::guts::typelist::typelist<at::Tensor const&> >, c10::Scalar (at::Tensor const&)>::call(c10::OperatorKernel*, at::Tensor const&) () from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#24 0x00007f5bf320cbbd in at::Tensor::item() const () from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#25 0x00007f5bf2d38b01 in at::native::is_nonzero(at::Tensor const&) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_cpu.so
#26 0x00007f5c0228beda in torch::autograd::THPVariable_is_nonzero(_object*, _object*) ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libtorch_python.so
#27 0x000055d4a4a75aba in _PyMethodDef_RawFastCallDict () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:482
#28 0x000055d4a4a75c81 in _PyCFunction_FastCallDict (func=0x7f5a61f18730, args=<optimized out>, nargs=<optimized out>, 
    kwargs=<optimized out>) at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:586
#29 0x000055d4a4aa2700 in call_unbound_noarg (self=0x7f59d8a71fa0, func=0x7f5a61f18730, unbound=0)
    at /tmp/build/80754af9/python_1588882889832/work/Objects/typeobject.c:1518
#30 slot_nb_bool () at /tmp/build/80754af9/python_1588882889832/work/Objects/typeobject.c:6251
#31 0x000055d4a4a3cd73 in PyObject_IsTrue () at /tmp/build/80754af9/python_1588882889832/work/Objects/object.c:1425
#32 0x000055d4a4a73418 in builtin_any () at /tmp/build/80754af9/python_1588882889832/work/Python/bltinmodule.c:427
#33 0x000055d4a4aa4abd in _PyMethodDef_RawFastCallKeywords () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:648
#34 0x000055d4a4aa4db1 in _PyCFunction_FastCallKeywords (func=0x7f5c2f0e4aa0, args=<optimized out>, nargs=<optimized out>, 
    kwnames=<optimized out>) at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:734
#35 0x000055d4a4b0fe94 in call_function (kwnames=0x0, oparg=1, pp_stack=<synthetic pointer>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:4568
#36 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3124
#37 0x000055d4a4aa420b in function_code_fastcall (globals=<optimized out>, nargs=2, args=<optimized out>, co=<optimized out>)
    at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:283
#38 _PyFunction_FastCallKeywords () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:408
#39 0x000055d4a4b0bbe6 in call_function (kwnames=0x0, oparg=<optimized out>, pp_stack=<synthetic pointer>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:4616
#40 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3124
#41 0x000055d4a4aa420b in function_code_fastcall (globals=<optimized out>, nargs=3, args=<optimized out>, co=<optimized out>)
    at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:283
#42 _PyFunction_FastCallKeywords () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:408
#43 0x000055d4a4b10229 in call_function (kwnames=0x0, oparg=<optimized out>, pp_stack=<synthetic pointer>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:4616
#44 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3093
#45 0x000055d4a4a54b00 in _PyEval_EvalCodeWithName () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3930
---Type <return> to continue, or q <return> to quit---
#46 0x000055d4a4aa4497 in _PyFunction_FastCallKeywords () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:433
#47 0x000055d4a4b0bbe6 in call_function (kwnames=0x0, oparg=<optimized out>, pp_stack=<synthetic pointer>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:4616
#48 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3124
#49 0x000055d4a4aa420b in function_code_fastcall (globals=<optimized out>, nargs=7, args=<optimized out>, co=<optimized out>)
    at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:283
#50 _PyFunction_FastCallKeywords () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:408
#51 0x000055d4a4b0bbe6 in call_function (kwnames=0x0, oparg=<optimized out>, pp_stack=<synthetic pointer>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:4616
#52 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3124
#53 0x000055d4a4a542b9 in _PyEval_EvalCodeWithName () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3930
#54 0x000055d4a4a551d4 in PyEval_EvalCodeEx () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3959
#55 0x000055d4a4a551fc in PyEval_EvalCode (co=<optimized out>, globals=<optimized out>, locals=<optimized out>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:524
#56 0x000055d4a4b1b2ed in builtin_exec_impl.isra.12 (locals=0x7f5c2f05cb40, globals=0x7f5c2f05cb40, source=0x7f5c2de93540)
    at /tmp/build/80754af9/python_1588882889832/work/Python/bltinmodule.c:1079
#57 builtin_exec () at /tmp/build/80754af9/python_1588882889832/work/Python/clinic/bltinmodule.c.h:283
#58 0x000055d4a4aa4b19 in _PyMethodDef_RawFastCallKeywords () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:655
#59 0x000055d4a4aa4db1 in _PyCFunction_FastCallKeywords (func=0x7f5c2f0e4e10, args=<optimized out>, nargs=<optimized out>, 
    kwnames=<optimized out>) at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:734
#60 0x000055d4a4b0fe94 in call_function (kwnames=0x0, oparg=2, pp_stack=<synthetic pointer>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:4568
#61 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3124
#62 0x000055d4a4a542b9 in _PyEval_EvalCodeWithName () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3930
#63 0x000055d4a4aa4435 in _PyFunction_FastCallKeywords () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:433
#64 0x000055d4a4b0bbe6 in call_function (kwnames=0x0, oparg=<optimized out>, pp_stack=<synthetic pointer>)
    at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:4616
#65 _PyEval_EvalFrameDefault () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3124
#66 0x000055d4a4a542b9 in _PyEval_EvalCodeWithName () at /tmp/build/80754af9/python_1588882889832/work/Python/ceval.c:3930
#67 0x000055d4a4a553e5 in _PyFunction_FastCallDict () at /tmp/build/80754af9/python_1588882889832/work/Objects/call.c:376
#68 0x000055d4a4b63ce7 in pymain_run_module () at /tmp/build/80754af9/python_1588882889832/work/Modules/main.c:355
#69 0x000055d4a4b7660b in pymain_run_python (pymain=0x7ffe7663edd0)
    at /tmp/build/80754af9/python_1588882889832/work/Modules/main.c:2899
#70 pymain_main () at /tmp/build/80754af9/python_1588882889832/work/Modules/main.c:3442
#71 0x000055d4a4b766fc in _Py_UnixMain () at /tmp/build/80754af9/python_1588882889832/work/Modules/main.c:3477
#72 0x00007f5c2e915b97 in __libc_start_main (main=0x55d4a4a353a0 <main>, argc=7, argv=0x7ffe7663ef28, init=<optimized out>, 
    fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffe7663ef18) at ../csu/libc-start.c:310
#73 0x000055d4a4b1b3c0 in _start () at ../sysdeps/x86_64/elf/start.S:103

  Id   Target Id         Frame 
* 1    Thread 0x7f5c2f11e740 (LWP 1197) "python" 0x00007ffe767b7b44 in clock_gettime ()
  17   Thread 0x7f5c0a1b6700 (LWP 2079) "jemalloc_bg_thd" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, 
    expected=0, futex_word=0x7f5bb6a0a5f4) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  18   Thread 0x7f5c0a9b7700 (LWP 2080) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  19   Thread 0x7f5c0f1b8700 (LWP 2081) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  20   Thread 0x7f5c0f9b9700 (LWP 2082) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  21   Thread 0x7f5bb5a24700 (LWP 2083) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  22   Thread 0x7f5bb5223700 (LWP 2084) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  23   Thread 0x7f5bb4a22700 (LWP 2085) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  24   Thread 0x7f5baffff700 (LWP 2086) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  25   Thread 0x7f5baf7fe700 (LWP 2087) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  26   Thread 0x7f5baeffd700 (LWP 2088) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  27   Thread 0x7f5bae7fc700 (LWP 2089) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  28   Thread 0x7f5badffb700 (LWP 2090) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  29   Thread 0x7f5bad7fa700 (LWP 2091) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  30   Thread 0x7f5bacff9700 (LWP 2092) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  31   Thread 0x7f5bac7f8700 (LWP 2093) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  32   Thread 0x7f5babff7700 (LWP 2094) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  33   Thread 0x7f5bab7f6700 (LWP 2095) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d4a7d28cc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  34   Thread 0x7f5baa5ff700 (LWP 2096) "jemalloc_bg_thd" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, 
    expected=0, futex_word=0x7f5bb6a0a6c4) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  35   Thread 0x7f5ba97ff700 (LWP 2097) "jemalloc_bg_thd" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, 
    expected=0, futex_word=0x7f5bb6a0a794) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  36   Thread 0x7f5b93fff700 (LWP 2098) "jemalloc_bg_thd" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, 
    expected=0, futex_word=0x7f5bb6a0a864) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  39   Thread 0x7f5b5b78b700 (LWP 2962) "python" 0x00007f5c2ea173e7 in accept4 (fd=10, addr=..., addr_len=0x7f5b5b78adf8, 
    flags=524288) at ../sysdeps/unix/sysv/linux/accept4.c:32
  40   Thread 0x7f5a608ff700 (LWP 2963) "python" 0x00007f5c2ea08cf9 in __GI___poll (fds=0x7f5980000bd0, nfds=10, timeout=100)
    at ../sysdeps/unix/sysv/linux/poll.c:29
  48   Thread 0x7f59e95ba700 (LWP 2992) "python" 0x00007f5c2ecf29f3 in futex_wait_cancelable (private=<optimized out>, expected=0, 
    futex_word=0x55d6cc21be9c) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  49   Thread 0x7f59eadbd700 (LWP 3000) "python" 0x00007f5c2aba5af1 in ?? ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libgomp-7c85b1e2.so.1
  50   Thread 0x7f59ea5bc700 (LWP 3001) "python" 0x00007f5c2aba5af1 in ?? ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libgomp-7c85b1e2.so.1
  51   Thread 0x7f59ed607700 (LWP 3002) "python" 0x00007f5c2aba5af1 in ?? ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libgomp-7c85b1e2.so.1
  52   Thread 0x7f59ebdbf700 (LWP 3003) "python" 0x00007f5c2aba5af1 in ?? ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libgomp-7c85b1e2.so.1
  53   Thread 0x7f59ede08700 (LWP 3004) "python" 0x00007f5c2aba5af1 in ?? ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libgomp-7c85b1e2.so.1
  54   Thread 0x7f59eb5be700 (LWP 3005) "python" 0x00007f5c2aba5af1 in ?? ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libgomp-7c85b1e2.so.1
  55   Thread 0x7f59e9dbb700 (LWP 3006) "python" 0x00007f5c2aba5af1 in ?? ()
   from /opt/conda/lib/python3.7/site-packages/torch/lib/libgomp-7c85b1e2.so.1
  1365 Thread 0x7f59dbfff700 (LWP 21113) "python" 0x00007f5c2ecf56e6 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, 
    expected=0, futex_word=0x7f59240046c0) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
  1366 Thread 0x7f59e670d700 (LWP 21114) "python" 0x00007f5c2ecf56e6 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, 
    expected=0, futex_word=0x7f5960002d40) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
  1367 Thread 0x7f59e570b700 (LWP 21115) "python" 0x00007f5c2ecf56e6 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, 
    expected=0, futex_word=0x7f5920004a80) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
  1368 Thread 0x7f59aa13f700 (LWP 21116) "python" 0x00007f5c2ecf56e6 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, 
    expected=0, futex_word=0x7f5914003d70) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
---Type <return> to continue, or q <return> to quit---
  1369 Thread 0x7f59e8db9700 (LWP 21117) "python" 0x00007f5c2ecf56e6 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, 
    expected=0, futex_word=0x7f593c000d50) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
  1370 Thread 0x7f59e5f0c700 (LWP 21118) "python" 0x00007f5c2ecf56e6 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, 
    expected=0, futex_word=0x7f5938000d50) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
  1371 Thread 0x7f59e4f0a700 (LWP 21119) "python" 0x00007f5c2ecf56e6 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, 
    expected=0, futex_word=0x7f591c005100) at ../sysdeps/unix/sysv/linux/futex-internal.h:205

Unfortunately I can’t share the code as is, so I’ll work on finding a minimum version that errors that I’ll be able to share.