Description

When ollama serve is started as a service user (e.g. www-data, wwwrun, nobody) and the current working directory is not accessible to that user, GPU detection silently fails and ollama falls back to library=cpu with no error message or warning.

Steps to Reproduce

# Fails silently → library=cpu
sudo -u www-data bash -c 'cd /root; ollama serve'

# Works → library=cuda
sudo -u www-data bash -c 'cd /tmp; ollama serve'

The only difference is the working directory. The environment (PATH, OLLAMA_HOST, CUDA env vars, DISPLAY, XAUTHORITY) is identical.

Environment

• OS: openSUSE Tumbleweed (Linux 6.x)
• GPU: NVIDIA RTX A3000 12GB (Optimus/PRIME, Dell Precision 7770)
• ollama built from source (current main)
• Service user: wwwrun (equivalent of www-data)

Root Cause

The GPU discovery subprocess (the internal ollama runner --ollama-engine process spawned by bootstrapDevices()) inherits the working directory of the parent process.

During CUDA backend initialization, libcuda.so (or a related NVIDIA library) accesses the working directory — most likely to write its JIT kernel cache. If the cwd is a directory the service user cannot access (e.g. /root with mode 700), the CUDA backend fails to initialize. Since the discovery subprocess discards stdout/stderr unless OLLAMA_DEBUG=2 (trace level), this failure is completely invisible to the operator. Ollama then falls back to CPU without any log entry at the default or info log level.

Impact

This is a silent failure — operators get no indication that GPU detection failed. The symptom (running on CPU instead of GPU) has many possible causes, and nothing in the logs points to the working directory as the culprit. Debugging this is extremely time-consuming.

Suggested Fix

Before spawning the discovery subprocess in bootstrapDevices(), change to a safe working directory:

os.Chdir(os.TempDir())

Alternatively (or additionally): log a warning at Info level when a GPU backend fails to load, so the failure is visible without requiring trace-level debugging.

Workaround

Ensure ollama is started from a directory accessible to the service user, e.g. by adding cd /tmp (or any world-accessible directory) before exec ollama serve in the start script.