[GitHub] [incubator-mxnet] szha commented on issue #18940: Floating point exception in mxnet.ndarray.op.SequenceReverse

[GitBox <gi...@apache.org>]

szha commented on issue #18940:
URL: https://github.com/apache/incubator-mxnet/issues/18940#issuecomment-678076744


   So here's the problem:
   ```
   % DMLC_LOG_STACK_TRACE_DEPTH=150 MXNET_ENGINE_TYPE=NaiveEngine lldb python3.7 -- test_18940.py
   (lldb) target create "python3.7"
   Current executable set to 'python3.7' (x86_64).
   (lldb) settings set -- target.run-args  "test_18940.py"
   (lldb) run
   Process 78879 launched: '/usr/local/bin/python3.7' (x86_64)
   Process 78879 stopped
   * thread #2, stop reason = exec
       frame #0: 0x0000000100006000 dyld`_dyld_start
   dyld`_dyld_start:
   ->  0x100006000 <+0>: popq   %rdi
       0x100006001 <+1>: pushq  $0x0
       0x100006003 <+3>: movq   %rsp, %rbp
       0x100006006 <+6>: andq   $-0x10, %rsp
   (lldb) cont
   Process 78879 resuming
   [23:52:34] ../src/engine/engine.cc:55: MXNet start using engine: NaiveEngine
   Process 78879 stopped
   * thread #2, queue = 'com.apple.main-thread', stop reason = EXC_ARITHMETIC (code=EXC_I386_DIV, subcode=0x0)
       frame #0: 0x0000000115861a13 libmxnet.dylib`mxnet::op::SequenceReverseOp<mshadow::cpu, float, float>::Forward(this=0x0000000123da0db0, ctx=0x00007ffeefbfc2b0, in_data=0x0000000127b7a2f8, req=0x00007ffeefbfc310, out_data=0x0000000127b7a340, aux_args=0x0000000127b7a328) at sequence_reverse-inl.h:139
      136 	    auto max_seq_len = in_data[seq_reverse::kData].size(0);
      137 	    auto n = in_data[seq_reverse::kData].size(1);
      138 	    auto total_size = in_data[seq_reverse::kData].Size();
   -> 139 	    auto rest_dim = static_cast<int>(total_size / n / max_seq_len);
      140
      141 	    Shape<3> s3 = Shape3(max_seq_len, n, rest_dim);
      142 	    Tensor<xpu, 3, DType> data =
   ```
   
   https://github.com/apache/incubator-mxnet/blob/9bdd4d6347c284770ee5bfe5ae98f1dabc283829/src/operator/sequence_reverse-inl.h#L139
   
   The code needs to guard against zero-size array for right operand of `/`, and we should add a smoke test to guard against such problem in this op, similar to https://github.com/apache/incubator-mxnet/pull/18972/files


----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org