Private synthetic runner stops with Segmentation Fault.

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Updated:October 1, 2026
Document ID:SPLK055050

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Applicability

Splunk Synthetic Monitoring

Description

A Splunk Synthetic Private Location container stops unexpectedly. When reviewing the container logs, a segmentation fault is observed. The error indicates a failure within the ethon library during browser test post-processing or result uploading. The issue may occur intermittently, ranging from a few days to two weeks after the container starts.

Example error message:

[2026-03-31 04:37:08 +0000 location_id:private-xxx-pl-latest] INFO: Saving screen captures /usr/local/bundle/gems/ethon-0.16.0/lib/ethon/easy/operations.rb:30: [BUG] Segmentation fault at 0x00005582e7c5efbd ruby 3.3.9 (2025-07-24 revision f5c772fc7c) [x86_64-linux]


Investigation

  1. Access the host machine where the Docker container is running.
  2. Retrieve the logs for the affected container: docker logs <container_id>
  3. Search the logs for the [BUG] Segmentation fault string and verify if it references ethon-0.16.0/lib/ethon/easy/operations.rb.
  4. Check the synthetic private runner version to ensure it is below 1.32.0.

Resolution

  1. Pull the latest Splunk Synthetics Runner image: docker pull quay.io/signalfx/splunk-synthetics-runner:latest
  2. Confirm the version is 1.32.0 or higher.
  3. Stop and remove the existing container.
  4. Start a new container and include the environment variable -e GC_PAUSE_FOR_CURL=true in the docker run command.
  5. Use the --restart always flag to ensure the container restarts automatically if an unexpected crash occurs.

PrivateSynthetic_Runner_Versions

Revision History

Revision Publish Date Comments
1.0
01-Oct-2026
Initial Release

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