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Concurrency Auditor (L3 Worker)

Specialized worker auditing concurrency and async patterns.

Purpose & Scope

• Worker in ln-620 coordinator pipeline
• Audit concurrency (Category 11: High Priority)
• Check race conditions, async/await, thread safety
• Calculate compliance score (X/10)

Inputs (from Coordinator)

Receives contextStore with tech stack, language, codebase root.

Workflow

1. Parse context
2. Check concurrency patterns
3. Collect findings
4. Calculate score
5. Return JSON

Audit Rules

1. Race Conditions

What: Shared state modified without synchronization

Detection Patterns:

Severity:

• CRITICAL: Race in payment/auth (payment, balance, auth, token in variable name)
• HIGH: Race in user-facing feature
• MEDIUM: Race in background job

Recommendation: Use locks, atomic operations, message queues

Effort: M-L

2. Missing Async/Await

What: Callback hell or unhandled promises

Detection Patterns:

Severity:

• HIGH: Fire-and-forget async (can cause data loss)
• MEDIUM: Callback hell (hard to maintain)
• LOW: Mixed Promise styles

Recommendation: Convert to async/await, always await or handle promises

Effort: M

3. Resource Contention

What: Multiple processes competing for same resource

Detection Patterns:

Severity:

• HIGH: File corruption risk, DB exhaustion
• MEDIUM: Performance degradation

Recommendation: Use connection pooling, file locking, asyncio.Lock

Effort: M

4. Thread Safety Violations

What: Shared mutable state without synchronization

Detection Patterns:

Grep patterns:

• Go unsafe: type.*struct\s*{[^}]*map\[ without sync.Mutex in same struct
• Python unsafe: global\s+\w+ in function + threading.Thread in same file

Severity: HIGH (data corruption possible)

Recommendation: Use thread-safe primitives

Effort: M

5. Deadlock Potential

What: Lock acquisition in inconsistent order

Detection Patterns:

Severity: HIGH (deadlock freezes application)

Recommendation: Consistent lock ordering, timeout locks (asyncio.wait_for)

Effort: L

6. Blocking I/O in Event Loop (Python asyncio)

What: Synchronous blocking calls inside async functions

Detection Patterns:

Severity:

• HIGH: Blocks entire event loop
• MEDIUM: Minor blocking (<100ms)

Recommendation: Use async alternatives

Effort: S-M

Scoring Algorithm

MANDATORY READ: Load shared/references/audit_scoring.md for unified scoring formula.

Output Format

{
  "category": "Concurrency",
  "score": 7,
  "total_issues": 4,
  "critical": 0,
  "high": 2,
  "medium": 2,
  "low": 0,
  "checks": [
    {"id": "race_conditions", "name": "Race Conditions", "status": "passed", "details": "No shared state modified without synchronization"},
    {"id": "missing_await", "name": "Missing Await", "status": "failed", "details": "2 fire-and-forget async calls found"},
    {"id": "resource_contention", "name": "Resource Contention", "status": "warning", "details": "DB pool_size=3 may be insufficient"},
    {"id": "thread_safety", "name": "Thread Safety", "status": "passed", "details": "All shared state properly synchronized"},
    {"id": "deadlock_potential", "name": "Deadlock Potential", "status": "passed", "details": "No nested locks or inconsistent ordering"},
    {"id": "blocking_io", "name": "Blocking I/O", "status": "failed", "details": "time.sleep in async context"}
  ],
  "findings": [
    {
      "severity": "HIGH",
      "location": "src/services/payment.ts:45",
      "issue": "Shared state 'balanceCache' modified without synchronization",
      "principle": "Thread Safety / Concurrency Control",
      "recommendation": "Use mutex or atomic operations for balanceCache updates",
      "effort": "M"
    }
  ]
}

Reference Files

• Audit scoring formula: shared/references/audit_scoring.md
• Audit output schema: shared/references/audit_output_schema.md

Critical Rules

• Do not auto-fix: Report only, concurrency fixes require careful human review
• Language-aware detection: Use language-specific patterns (Go sync.Mutex, Python asyncio.Lock, Java synchronized)
• Effort realism: S = <1h, M = 1-4h, L = >4h
• Critical path escalation: Race conditions in payment/auth = CRITICAL, regardless of other factors
• Exclusions: Skip test files, skip single-threaded CLI tools, skip generated code

Definition of Done

• contextStore parsed (language and concurrency model identified)
• All 6 checks completed (race conditions, missing await, resource contention, thread safety, deadlock potential, blocking I/O)
• Findings collected with severity, location, effort, recommendation
• Score calculated per shared/references/audit_scoring.md
• JSON returned to coordinator

Version: 3.0.0 Last Updated: 2025-12-23