FreeBSD 13 Kernel Module Fails to Load at Boot

📖 ~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

Some FreeBSD 13 features rely on kernel modules that must load early during boot.

Environment & Reproduction

Expected functionality is absent after reboot even though manual kldload succeeds later.

Root Cause Analysis

Incorrect loader.conf syntax, missing module package, or module built for different kernel ABI.

Quick Triage

Check kldstat, try kldload , and inspect /boot/loader.conf with boot dmesg output.

Step-by-Step Diagnosis

Confirm exact module name and kernel version compatibility. image_ref=0

Solution – Primary Fix

Install required package if missing, set module_load in loader.conf, and reboot to verify automatic loading. image_ref=1

Solution – Alternative Approaches

Use service kld start only when appropriate, but prefer loader.conf for reliable early boot initialization.

Verification & Acceptance Criteria

Keep module toggles documented and avoid duplicate directives across local and generated loader files.

Rollback Plan

If module impacts networking, validate pf and interface behavior after module activation.

Prevention & Hardening

After reboot, verify kldstat includes target module and dependent subsystem is operational.

Related Errors & Cross-Refs

Track kernel upgrades and retest third-party module compatibility in staging first.

Related tutorial: View the step-by-step tutorial for freebsd-13.

View all freebsd-13 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

See man kldload, man loader.conf, and FreeBSD kernel module administration docs.