Taichi: [BUG] get a Segmentation Fault while invoke .norm() or .dot() of Vector

Created on 6 Jun 2020 · 9Comments · Source: taichi-dev/taichi

Describe the bug
get a Segmentation Fault while invoke .norm()
environment: ubuntu 16.04 LTS / python 3.6.9 / taichi 0.6.7

Log/Screenshots

[E 06/06/20 20:55:45.920] Received signal 11 (Segmentation fault)
***********************************
* Taichi Compiler Stack Traceback *
***********************************
/usr/Software/anaconda3/lib/python3.6/site-packages/taichi/core/../lib/taichi_core.so: taichi::Logger::error(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)
/usr/Software/anaconda3/lib/python3.6/site-packages/taichi/core/../lib/taichi_core.so: taichi::signal_handler(int)
/lib/x86_64-linux-gnu/libc.so.6(+0x354b0) [0x7ff227ba24b0]
/usr/Software/anaconda3/lib/python3.6/site-packages/taichi/core/../lib/taichi_core.so: taichi::lang::current_ast_builder()
/usr/Software/anaconda3/lib/python3.6/site-packages/taichi/core/../lib/taichi_core.so: taichi::lang::Var(taichi::lang::Expr const&)
/usr/Software/anaconda3/lib/python3.6/site-packages/taichi/core/../lib/taichi_core.so(+0x6f0a1a) [0x7ff1cad97a1a]
/usr/Software/anaconda3/lib/python3.6/site-packages/taichi/core/../lib/taichi_core.so(+0x655bef) [0x7ff1cacfcbef]
/usr/Software/anaconda3/bin/python: _PyCFunction_FastCallDict
/usr/Software/anaconda3/bin/python(+0x199abc) [0x55f39afb5abc]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python(+0x193ed6) [0x55f39afafed6]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python: _PyFunction_FastCallDict
/usr/Software/anaconda3/bin/python: _PyObject_FastCallDict
/usr/Software/anaconda3/bin/python: _PyObject_Call_Prepend
/usr/Software/anaconda3/bin/python: PyObject_Call
/usr/Software/anaconda3/bin/python(+0x16b6b0) [0x55f39af876b0]
/usr/Software/anaconda3/bin/python(+0x1f100e) [0x55f39b00d00e]
/usr/Software/anaconda3/bin/python: PyNumber_Power
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python(+0x193e73) [0x55f39afafe73]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python: PyEval_EvalCodeEx
/usr/Software/anaconda3/bin/python: PyEval_EvalCode
/usr/Software/anaconda3/bin/python(+0x1ba167) [0x55f39afd6167]
/usr/Software/anaconda3/bin/python: _PyCFunction_FastCallDict
/usr/Software/anaconda3/bin/python(+0x199abc) [0x55f39afb5abc]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python: _PyGen_Send
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python: _PyGen_Send
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python: _PyGen_Send
/usr/Software/anaconda3/bin/python: _PyCFunction_FastCallDict
/usr/Software/anaconda3/bin/python(+0x199abc) [0x55f39afb5abc]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python(+0x193ed6) [0x55f39afafed6]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python(+0x193e73) [0x55f39afafe73]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python(+0x193e73) [0x55f39afafe73]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x193c5b) [0x55f39afafc5b]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python: _PyFunction_FastCallDict
/usr/Software/anaconda3/bin/python: _PyObject_FastCallDict
/usr/Software/anaconda3/bin/python: _PyObject_Call_Prepend
/usr/Software/anaconda3/bin/python: PyObject_Call
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python(+0x192e66) [0x55f39afaee66]
/usr/Software/anaconda3/bin/python(+0x193ed6) [0x55f39afafed6]
/usr/Software/anaconda3/bin/python(+0x199b95) [0x55f39afb5b95]
/usr/Software/anaconda3/bin/python: _PyEval_EvalFrameDefault
/usr/Software/anaconda3/bin/python: PyEval_EvalCodeEx
/usr/Software/anaconda3/bin/python: PyEval_EvalCode
/usr/Software/anaconda3/bin/python(+0x215744) [0x55f39b031744]
/usr/Software/anaconda3/bin/python: PyRun_FileExFlags
/usr/Software/anaconda3/bin/python: PyRun_SimpleFileExFlags
/usr/Software/anaconda3/bin/python: Py_Main
/usr/Software/anaconda3/bin/python: main
/lib/x86_64-linux-gnu/libc.so.6: __libc_start_main
/usr/Software/anaconda3/bin/python(+0x1c3160) [0x55f39afdf160]

To Reproduce

import taichi as ti
a = ti.Vector([3,4,5])
print(a.norm())
print(a.dot(a))

potential bug wontfix

Source

the-butterfly

Most helpful comment

The issue seems to be related to print(a.norm()), I could reproduce it with:

import taichi as ti

ti.init(arch=ti.cpu)
ti.reset()

@ti.kernel
def main():
    a = ti.Vector([3,4])
    a.norm()  # -> OK
    print(a.norm())  # -> Error out

main()

This line looks suspicious:
Screen Shot 2020-06-07 at 12 13 37 AM

rexwangcc on 7 Jun 2020

👍2

All 9 comments

same as outer_product

the-butterfly on 6 Jun 2020

It seems that you're invoking norm and dot in Python-scope? For now, they can only be invoked in Taichi-scope, i.e.:

@ti.kernel
def taichi_kernel():
  a = ti.Vector([3,4,5])
  print(a.norm())
  print(a.dot(a))

taichi_kernel()

Sorry for the confusing segmentation fault here, it will be replace with a friendly message in next release :)

archibate on 6 Jun 2020

👍1

Yeah for now these functions can only be called in Taichi-scope. We will gradually add Python-scope support in #1008

yuanming-hu on 6 Jun 2020

It seems that you're invoking norm and dot in Python-scope? For now, they can only be invoked in Taichi-scope, i.e.:
@ti.kernel
def taichi_kernel():
  a = ti.Vector([3,4,5])
  print(a.norm())
  print(a.dot(a))

taichi_kernel()
Sorry for the confusing segmentation fault here, it will be replace with a friendly message in next release :)

These functions cannot be called in Taichi-scope.

wsAndy on 7 Jun 2020

Did you run ti.init()? Does run from cmd or bash solve you problem?

archibate on 7 Jun 2020

Did you run ti.init()? Does run from cmd or bash solve you problem?

Yes, but the problem remains.
environment: ubuntu18.04\ python 3.6.9\ taichi 0.6.7

wsAndy on 7 Jun 2020

The issue seems to be related to print(a.norm()), I could reproduce it with:

import taichi as ti

ti.init(arch=ti.cpu)
ti.reset()

@ti.kernel
def main():
    a = ti.Vector([3,4])
    a.norm()  # -> OK
    print(a.norm())  # -> Error out

main()

This line looks suspicious:
Screen Shot 2020-06-07 at 12 13 37 AM

rexwangcc on 7 Jun 2020

👍2

It seems that ti.Vector([3.0, 4.0]) solve the problem.
Because x.norm() needs sqrt, whose operand is i32 in this case.
Therefore it gives an error: sqrt is for float only!
@xumingkuan Can we promote operand to float for math functions like sqrt? So that ti.sqrt(3) won't result in an error?

archibate on 7 Jun 2020

👍1

Replaced by #1172.

archibate on 7 Jun 2020

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