Ubuntu 22.04 kdump Fails to Capture Kernel Crash Dumps

📖 ~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

Kernel panic occurs but no vmcore is generated, preventing root-cause analysis for critical crashes.

Environment & Reproduction

Ubuntu 22.04 servers intended to run kdump-tools with crashkernel memory reservation and dedicated dump target.

Root Cause Analysis

Missing crashkernel parameter, disabled kdump service, or inaccessible dump target prevents second kernel from saving vmcore.

Quick Triage

Check /proc/cmdline for crashkernel, verify kdump-tools service state, and confirm dump path capacity/permissions.

Step-by-Step Diagnosis

Inspect /etc/default/kdump-tools, validate initramfs includes kdump components, and review previous panic logs for dump handoff errors.

Solution – Primary Fix

Set crashkernel parameter in GRUB, enable kdump-tools, regenerate grub and initramfs, and test with controlled crash trigger.

Solution – Alternative Approaches

Store dumps over network target, increase reserved memory, or use vendor crash capture mechanisms if required.

Verification & Acceptance Criteria

Test panic creates vmcore at configured location and analysis tools can read dump successfully.

Rollback Plan

Remove crashkernel changes and disable kdump-tools if reserved memory impacts workload capacity.

Prevention & Hardening

Include kdump validation in platform commissioning and monitor dump service health after kernel updates.

Related Errors & Cross-Refs

Related Ubuntu reliability topics include random kernel panic loops and incomplete post-mortem data retention.

Related tutorial: View the step-by-step tutorial for Ubuntu 22.04 LTS.

View all Ubuntu 22.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu kdump-tools documentation, kernel crash dump guide, and kexec/kdump operational references.