SELinux AVC Flood Causing Performance Degradation

📖 ~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

Frequent AVC denials generate heavy log volume, elevated CPU, and degraded response of affected services.

Environment & Reproduction

Occurs after deploying new binaries, changing data paths, or introducing firewalld/SELinux policy drift.

Root Cause Analysis

Service behavior conflicts with existing SELinux policy, producing repetitive denied operations and journal churn.

Quick Triage

Run `ausearch -m avc -ts recent`, `journalctl -xe`, and confirm service/process context mappings.

Step-by-Step Diagnosis

Identify dominant denial pattern, map to policy domain, and verify whether path labeling or booleans are incorrect.

Solution – Primary Fix

Apply proper context/boolean or minimal policy module, restart service, and keep SELinux enforcing.

Solution – Alternative Approaches

Refactor service paths to standard labels and reduce noisy retry loops that amplify denial storms.

Verification & Acceptance Criteria

AVC rate drops to baseline, CPU usage normalizes, and service throughput returns to target.

Rollback Plan

Remove custom policy artifacts and restore prior service config if behavior deviates from expected.

Prevention & Hardening

Embed SELinux validation in release pipeline and monitor AVC rate spikes as early warning signal.

Related Errors & Cross-Refs

`ausearch -m avc -ts recent | audit2allow -w && systemctl restart && journalctl -u -n 80`

Related tutorial: View the step-by-step tutorial for rhel-7.

View all rhel-7 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

RHEL 7 SELinux troubleshooting and policy authoring references for secure, stable production operations.