Vector Assertion Failure in InferenceSession Init with Hotplugged-Off Cores on ARM (v1.21.0)

[PapperYZ]

Describe the issue

Environment:

• Device: OrangePi 5 Plus (4x A76 + 4x A55)
• Config: Any cores disabled (e.g., echo 0 > /sys/devices/system/cpu/cpu[4-7]/online)
• OS: Ubuntu 22.04
• ONNX Runtime: v1.21.0
• Python: 3.10
• GCC: 14 (gcc-toolset-14)

Issue:

• Crashes during InferenceSession init with
  /opt/rh/gcc-toolset-14/root/usr/include/c++/14/bits/stl_vector.h:1130: Assertion '__n < this->size()' failed.
• Succeeds when all 8 cores are online (even if restricted to 4 via taskset -c 4-7) or on a 4x A53 system with no hotplugging.
• Fails whenever any cores are hotplugged off (e.g., 4x A55 only or A76 + partial A55).

Observations:

• os.cpu_count() correctly reports online cores (e.g., 4).
• OMP_NUM_THREADS=1 doesn’t fix it—issue is in init, not runtime threading.
• Suspect: Mishandles CPU topology when cores are hotplugged off (e.g., uses present instead of online).

To reproduce

disable 4 cores with command below

echo 1 | sudo tee /sys/devices/system/cpu/cpu[0-3]/online
echo 0 | sudo tee /sys/devices/system/cpu/cpu[4-7]/online

and run simple python script below:

import onnxruntime
model_path = "/path/to/resnet50_v1.onnx"
session = onnxruntime.InferenceSession(model_path, providers=["CPUExecutionProvider"])
print("Session initialized successfully")

You will see:

Urgency

please help to solve the issue soon, it should be a quick fix... it is currently preventing us with a benchmark reference with our ASIC with similar cores.

Platform

Linux

OS Version

Ubuntu 22.04

ONNX Runtime Installation

Released Package

ONNX Runtime Version or Commit ID

ONNX Runtime: v1.21.0

ONNX Runtime API

Python

Architecture

ARM64

Execution Provider

Default CPU

Execution Provider Library Version

No response

[snnn]

Could you please build ONNX Runtime in debug mode and generate a stacktrace?
Doc: https://onnxruntime.ai/docs/build/inferencing.html

[PapperYZ]

Sorry, I do not know how to do that
I have already provided clear reproduce steps, would you try to look into that?

[github-actions]

This issue has been automatically marked as stale due to inactivity and will be closed in 30 days if no further activity occurs. If further support is needed, please provide an update and/or more details.