RHEL 9 kernel update completed but old kernel still boots

📖 ~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

After dnf update and reboot, uname -r still shows an older kernel.

Environment & Reproduction

New kernel package exists but default boot entry points to previous version.

Root Cause Analysis

Bootloader entry mismatch, manual default override, or interrupted kernel install tasks.

Quick Triage

Compare rpm -q kernel, uname -r, and grubby –default-kernel output.

Step-by-Step Diagnosis

Use grubby –info=ALL to identify the active default and available kernel images.

Solution – Primary Fix

Apply grubby –set-default with the desired vmlinuz path and confirm before reboot.

Solution – Alternative Approaches

If entries are inconsistent, rebuild grub config according to platform boot mode.

Verification & Acceptance Criteria

Validate kernel and initramfs artifacts under /boot and reinstall package if corrupted.

Rollback Plan

Ensure /boot file contexts are standard after manual file operations.

Prevention & Hardening

Reboot in maintenance window and watch boot target and journal for anomalies.

Related Errors & Cross-Refs

Automate kernel lifecycle checks after each patch cycle with compliance reporting.

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

Confirm uname -r matches desired kernel and systemctl reports healthy boot state.