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Segfault when simulating circuits with specific number of qubits #1878

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g33kex opened this issue Jul 24, 2023 · 2 comments
Closed

Segfault when simulating circuits with specific number of qubits #1878

g33kex opened this issue Jul 24, 2023 · 2 comments
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@doichanj
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@g33kex
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g33kex commented Jul 24, 2023

Informations

  • Qiskit Aer version: 0.12.2
  • Python version: 3.11.3
  • Operating system: Archlinux

What is the current behavior?

The following code leads to a segfault when running the simulator:

from qiskit import ClassicalRegister, QuantumRegister, QuantumCircuit
from qiskit import transpile
from qiskit_aer.backends import AerSimulator

n=39
#n=52 # Doesn't segfault with n=52
A = QuantumRegister(n)
B = QuantumRegister(n)
m = ClassicalRegister(len(A))
qc = QuantumCircuit(A, B, m)
qc.ccx(B[0], A[0], A[1])
#qc.ccx(A[2], A[0], A[1]) # Using this gate will not segfault if n=39 but will segfault if n=81
qc.measure(A, m)
backend_sim = AerSimulator()
transpiled = transpile(qc, backend_sim)
print("Circuit transpiled.")
job_sim = backend_sim.run(transpiled, shots=1) # This triggers a segmentation fault
print("No segfault!")

When n=39 the circuit has 78 qubits, 39 classical bits and a single Toffoli gate. The simulation step segfaults.
However if n=52, the circuit runs without segfault. This also happens with different circuits. The process doesn't run out of memory.
Also for n=39, doing the Toffoli gate between qubits from only register A doesn't result in segfault, but using qubits from both registers results in a segfault. But if we now set n=81, it segfaults in both cases. But if we set n=96, it doesn't segfault anymore.

Steps to reproduce the problem

Run code above. It will print "Circuit transpiled." and then segfault. I tried it on ArchLinux and Windows.

What is the expected behavior?

The program should not segfault.

Suggested solutions

I have no idea where this bug comes from, it is really weird.

Here is the core dump from the system logs:

Jul 24 10:58:46 computer systemd-coredump[79394]: [🡕] Process 79345 (python3) of user 1000 dumped core.
                                                 
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/spatial/_qhull.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/spatial/_qhull.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_interpolative.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_interpolative.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/_cobyla.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/_cobyla.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/_lbfgsb.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/_lbfgsb.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/_trlib/_trlib.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/_trlib/_trlib.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_lsoda.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_lsoda.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_dop.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_dop.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/special/_specfun.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/special/_specfun.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/special/_ufuncs.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/special/_ufuncs.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/sparse/linalg/_eigen/arpack/_arpack.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/sparse/linalg/_eigen/arpack/_arpack.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_vode.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_vode.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/sparse/linalg/_dsolve/_superlu.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/sparse/linalg/_dsolve/_superlu.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_flapack.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_flapack.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_quadpack.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_quadpack.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy.libs/libopenblasp-r0-41284840.3.18.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy.libs/libopenblasp-r0-41284840.3.18.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/sparse/linalg/_isolve/_iterative.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/sparse/linalg/_isolve/_iterative.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/cython_blas.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/cython_blas.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer/pulse/controllers/pulse_utils.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer/pulse/controllers/pulse_utils.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer.libs/libgfortran-91cc3cb1.so.3.0.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer.libs/libgfortran-91cc3cb1.so.3.0.0
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/cython_lapack.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/cython_lapack.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer.libs/libgomp-a34b3233.so.1.0.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer.libs/libgomp-a34b3233.so.1.0.0
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer.libs/libopenblas-r0-f650aae0.3.3.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer.libs/libopenblas-r0-f650aae0.3.3.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/__nnls.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/optimize/__nnls.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer/backends/controller_wrappers.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/qiskit_aer/backends/controller_wrappers.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_fblas.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_fblas.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libXau-154567c4.so.6.0.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libXau-154567c4.so.6.0.0
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/special/_ellip_harm_2.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/special/_ellip_harm_2.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libtiff-189042a3.so.6.0.1 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libtiff-189042a3.so.6.0.1
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libopenjp2-20e347f0.so.2.5.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libopenjp2-20e347f0.so.2.5.0
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libjpeg-dab02bf4.so.62.3.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libjpeg-dab02bf4.so.62.3.0
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libmpfr-aad5016b.so.6.1.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libmpfr-aad5016b.so.6.1.0
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/liblzma-9dd5c569.so.5.4.3 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/liblzma-9dd5c569.so.5.4.3
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libflint-b75bea04.so.15.0.1 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libflint-b75bea04.so.15.0.1
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libxcb-cd9c1006.so.1.1.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/Pillow.libs/libxcb-cd9c1006.so.1.1.0
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine/lib/symengine_wrapper.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine/lib/symengine_wrapper.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libzstd-3c9d0529.so.1.5.2 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libzstd-3c9d0529.so.1.5.2
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libgmp-b6b552a9.so.10.4.1 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libgmp-b6b552a9.so.10.4.1
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libmpc-bf04043a.so.3.2.1 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/symengine.libs/libmpc-bf04043a.so.3.2.1
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy.libs/libquadmath-96973f99.so.0.0.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy.libs/libquadmath-96973f99.so.0.0.0
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy.libs/libgfortran-040039e1.so.5.0.0 without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy.libs/libgfortran-040039e1.so.5.0.0
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_odepack.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/integrate/_odepack.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_flinalg.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/scipy/linalg/_flinalg.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy.libs/libopenblas64_p-r0-742d56dc.3.20.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy.libs/libopenblas64_p-r0-742d56dc.3.20.so
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy/linalg/_umath_linalg.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy/linalg/_umath_linalg.cpython-311-x86_64-linux-gnu.so
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy/core/_multiarray_umath.cpython-311-x86_64-linux-gnu.so without build-id.
                                                 Module /test/.venv/lib/python3.11/site-packages/numpy/core/_multiarray_umath.cpython-311-x86_64-linux-gnu.so
                                                 Stack trace of thread 79391:
                                                 #0  0x00007fb5e76497bb n/a (/test/.venv/lib/python3.11/site-packages/qiskit_aer/backends/controller_wrappers.cpython-311-x86_64-linux-gnu.so + 0x497bb)
                                                 #1  0x5445445f3131444e n/a (n/a + 0x0)
                                                 ELF object binary architecture: AMD x86-64
@g33kex g33kex added the bug Something isn't working label Jul 24, 2023
@doichanj doichanj self-assigned this Jul 26, 2023
@doichanj
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I found issue in calculating required memory for statevector because it uses 64 bits integer that overflows when number of qubits so large. This issue causes wrong method selection (statevector was selected) and segmentation fault.

qiskit-aer/src/simulators/statevector/qubitvector.hpp

Lines 939 to 946 in b4e393c

template <typename data_t>
size_t QubitVector<data_t>::required_memory_mb(uint_t num_qubits) const {
size_t unit = std::log2(sizeof(std::complex<data_t>));
size_t shift_mb = std::max<int_t>(0, num_qubits + unit - 20);
size_t mem_mb = 1ULL << shift_mb;
return mem_mb;
}

@doichanj doichanj mentioned this issue Jul 26, 2023
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@g33kex
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g33kex commented Jul 28, 2023

Thank you! This fixes the issue in all of my test cases.

@g33kex g33kex closed this as completed Jul 28, 2023
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