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PyArrow makes SIGSEGV #16925
Description
Environment
- Qiskit version: v2.5.0
- Python version: 3.13.5
- Operating system: MacOS Tahoe Version 26.5.1 (25F80)
- PyArrow: 24.0.0
What is happening?
Importing PyArrow 24.0.0 makes simplify() crash, with a SIGSEGV.
How can we reproduce the issue?
Install PyArrow>=24.0.0 and Qiskit>=2.5.0
from qiskit.quantum_info import SparsePauliOp
def main():
print("Teset before import pyarrow")
print("before", flush=True)
op = SparsePauliOp.from_list([
("IIII", 0.5),
("IIII", 0.5),
("IIZZ", 1.0),
("IZIZ", 1.0),
("ZIIZ", 1.0),
("IZZI", 1.0),
("ZIZI", 1.0),
("ZZII", 1.0),
])
print("before simplify", flush=True)
op = op.simplify()
print("after simplify", flush=True)
import pyarrow
print("Test after import pyarrow", flush=True)
print("data loaded")
print("before", flush=True)
op = SparsePauliOp.from_list([
("IIII", 0.5),
("IIII", 0.5),
("IIZZ", 1.0),
("IZIZ", 1.0),
("ZIIZ", 1.0),
("IZZI", 1.0),
("ZIZI", 1.0),
("ZZII", 1.0),
])
print("before simplify", flush=True)
op = op.simplify()
print("after simplify", flush=True)
print("before simplify", flush=True)
op = op.simplify()
print("after simplify", flush=True)
if __name__ == "__main__":
main()What should happen?
It should run and print:
Teset before import pyarrow
before
before simplify
after simplify
Test after import pyarrow
data loaded
before
before simplify
after simplify
before simplify
after simplify
Instead, it raises a SIGSEGV and prints:
Teset before import pyarrow
before
before simplify
after simplify
Test after import pyarrow
data loaded
before
before simplify
Any suggestions?
Downgroading to PyArrow 23 worked for me, but I don't know why it's related, I didn't investigate the root cause.
Activity
jakelishman commentedon Sep 4, 2026
As best as I can tell, this is a bug in the
mimallocconfiguration of PyArrow 24 (apache/arrow#50549) and exacerbated by an underlying flaw inmimallocitself (microsoft/mimalloc#1327). Upgrading to PyArrow 25 or downgrading to 23 should fix it.It's not entirely obvious to me if Qiskit also has some sort of latent misconfiguration bug in its
mimallocbuild (though if we do, it might be something we need to contribute upstream to the Rustmimalloccrate). We could/should probably try and reproduce this by building our own Python extension from Rust using the same sorts of mechanisms as Qiskit, and see if they can both co-exist.AnitaGeorge404 commentedon Sep 24, 2026
Hii Jake Lishman (@jakelishman), I’d be happy to help with this. I can try reproducing the PyArrow 24/mimalloc interaction using a small Rust/Python extension built similarly to Qiskit, and check whether there’s anything Qiskit-specific that needs fixing or documenting. If that would be useful, could you assign this issue to me?