Driver Verifier Triage

Load windbg-diagnostic-method first if it is not already loaded in this conversation, and apply it throughout for evidence ranking, hypothesis testing, confidence calibration, independent review, and report validation. This skill adds the bug-family-specific commands and evidence requirements.

Scope

Driver Verifier checks kernel driver contracts. Application Verifier is a different user-mode facility; use windbg-user-heap-corruption-investigation for its heap stops. Enabled Driver Verifier flags alone do not prove a contract violation.

Use this skill when a verifier-class bugcheck or analysis identifies an actual violation. Examples include 0xC4, 0xC9, and 0xE6; inspect the exact code and parameters rather than treating every stop as the same family.

Workflow

1. Preserve code, subcode, and active configuration

!analyze -v
.bugcheck
!verifier
k

Record the bugcheck, subtype/subcode, offending operation and driver when reported, enabled checks, target build, and evidence availability. Decode each subcode against its documented contract. Existing output may be incomplete in a small dump; do not discard captured evidence merely because live configuration is now different.

2. Decode available I/O history

When the violation supplies an appropriate IRP address and I/O verification state is available:

!iovirp <irp-address>
!irp <irp-address>

Shadow state may preserve information lost from the live request. Correlate it with the decoded contract and use windbg-kernel-irp-lifecycle-triage for completion, cancellation, pending state, and ownership.

3. Recover context or follow dependencies

• Saved exception/trap context: windbg-kernel-bugcheck-triage.
• Lock-order evidence: windbg-kernel-lock-deadlock-triage.
• Outstanding or power request: windbg-kernel-irp-lifecycle-triage.

Avoid cyclic dispatch. Carry the evidence already collected to the next skill; re-enter only when a distinct evidence requirement exists.

4. Investigate uncovered violations

For a generic DDI violation, identify the exact precondition (IRQL, lifetime, parameters, or ownership) and the driver call that broke it. For a DMA violation, inspect supported adapter/map/unmap and buffer-lifetime evidence for that subcode. This package does not provide a specialized decoder for every DDI or DMA case; state the gap and continue from documentation and driver source.

Controlled repro

Do not enable Driver Verifier without approval. It can deliberately crash the system and expose boot-critical defects. Use a recoverable test machine, save the current configuration, select relevant vendor drivers/checks, and agree on rollback before restarting. Do not verify every installed driver by default.

Read-only configuration inspection on a test machine:

verifier /querysettings

verifier /reset clears settings and normally requires a restart to stop verification; it is a configuration change, not a harmless query. Restore previous intentional settings rather than unconditionally clearing them.

Validation

Name the exact violated contract, link the recorded operation to driver source, and test that the remedy satisfies it under the same checks and workload. Record dump/verification limitations and unverified assumptions. Passing a single repro is not proof that every driver path is safe.

References

• Driver Verifier
• Verifier extension
• I/O verifier IRP extension
• 0xC4 verifier violation

Feedback

Follow FEEDBACK.md and submit reviewed, sanitized feedback to WinDbg-Feedback. Include windbg-kernel-verifier-triage and the package version from plugin.json; do not automatically upload dumps or proprietary driver source.