Kernel Updated But Old Kernel Still Running

📖 ~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

dnf reports new kernel installed but uname -r still shows previous kernel version.

Environment & Reproduction

System has not been rebooted into updated kernel or default grub entry differs.

Root Cause Analysis

Run rpm -q kernel and compare package versions with running kernel.

Quick Triage

Run needs-restarting -r from dnf-utils or dnf-plugins-core packages.

Step-by-Step Diagnosis

Plan and execute systemctl reboot during maintenance window.

Solution – Primary Fix

After reboot, run uname -r and grubby –default-kernel for confirmation.

Solution – Alternative Approaches

Use grubby –info=ALL to ensure expected kernel is selected by default.

Verification & Acceptance Criteria

Validate kdump service and reserved memory after kernel transitions.

Rollback Plan

Run journalctl -b -1 for previous boot issues if reboot failed unexpectedly.

Prevention & Hardening

Security fixes and driver improvements remain inactive until reboot completes.

Related Errors & Cross-Refs

Track kernel update plus reboot completion as separate compliance steps.

Related tutorial: View the step-by-step tutorial for rhel-9.

View all rhel-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Automate post-patch reboot orchestration for nodes requiring new kernel activation.