Skip to content

SIGILL crash on Intel Xeon E5-2673 v2 (Ivy Bridge) even with LlamaLib v2.0.5 noavx / avx libraries #413

Description

@Marksonthegamer

Describe the bug

When using LLMUnity with LlamaLib v2.0.5 on Ubuntu 24.04, the application crashes with SIGILL (Illegal Instruction) during library initialization on an Intel Xeon E5-2673 v2 (Ivy Bridge-EP, 2013).

The crash always occurs inside ggml_cpu_init → ggml_backend_cpu_reg (called from llama_supports_gpu_offload / architecture detection), regardless of whether the Vulkan, AVX, or noavx backend is loaded.

Setting Num GPU Layers = 0 and forcing only the noavx library does not prevent the crash.

The same behaviour was previously observed with the older undreamai 1.2.5 packages.

The CPU supports AVX but not AVX2/FMA. It appears the pre-built binaries (including the noavx variant) still contain instructions that are illegal on Ivy Bridge. A binary built with -march=x86-64 / fully disabled AVX2+FMA that is guaranteed safe on pre-Haswell CPUs would be greatly appreciated, or at least clearer documentation on the minimum supported CPU generation.

Player.log

Steps to reproduce

No response

LLMUnity version

2.0.5

Operating System

Linux

Metadata

Metadata

Assignees

No one assigned

    Labels

    bugSomething isn't working

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions