FreeBSD 12 – expected core dumps are missing due to kern.corefile configuration

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Crashes produce no core files, delaying root-cause analysis.

Environment & Reproduction

Appears after limit, sysctl, or filesystem permission hardening.

Root Cause Analysis

Core dump flag, size limits, or destination path prevents writes.

Quick Triage

Check ulimit, kern.coredump, kern.corefile, and directory permissions.

Step-by-Step Diagnosis

Run controlled crash test and inspect generated artifacts.

Solution – Primary Fix

Enable coredumps and configure a stable writable core path.

Solution – Alternative Approaches

Set per-service dump behavior while keeping global defaults strict.

Verification & Acceptance Criteria

Controlled crash generates readable core file in expected location.

Rollback Plan

Disable coredumps and reset path if policy requires rollback.

Prevention & Hardening

Rotate old core files and enforce retention to prevent disk fill.

Related Errors & Cross-Refs

Related to read-only datasets and jail capability restrictions.

Related tutorial: View the step-by-step tutorial for FreeBSD 12.

View all FreeBSD 12 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

FreeBSD core dump handling and gdb analysis workflows.