ThordekkCore/COMPLETE_DEADLOCK_AUDIT.md

COMPLETE DEADLOCK AUDIT - All Map Access Points from Worker Threads

EXECUTION FLOW CONFIRMATION

UpdateAI (line 314) → UpdateManagers (line 502) → ALL MANAGER UPDATE CALLS

This means ALL managers listed below run on WORKER THREADS from the thread pool!

CRITICAL FINDINGS

Total ObjectAccessor Calls from Worker Threads: 31 calls

System	Files	ObjectAccessor Calls	Severity
TargetScanner	1	✅ FIXED (was 3)	CRITICAL (was main bottleneck)
ClassAI	2	✅ PARTIALLY FIXED (5 remaining in helpers)	HIGH
QuestManager	3	❌ 11 calls	CRITICAL
GatheringManager	1	❌ 5 calls	CRITICAL
Strategy Systems	3	❌ 10 calls	HIGH

---

1. TargetScanner (FIXED ✅)

File: src/modules/Playerbot/AI/Combat/TargetScanner.cpp

Status: COMPLETELY FIXED - Returns GUIDs, BotAI resolves on main thread

Previous Calls:

• Line 328: ObjectAccessor::GetUnit() in FindAllHostiles() - ELIMINATED
• Line 183-264: FindBestTarget() - ELIMINATED
• Line 128-181: FindNearestHostile() - ELIMINATED

Impact: MASSIVE - Called hundreds of times per second across thousands of bots

---

2. ClassAI Systems (PARTIALLY FIXED ⚠️)

UnholySpecialization.cpp (5 errors remaining)

File: src/modules/Playerbot/AI/ClassAI/DeathKnights/UnholySpecialization.cpp

Status: Main methods fixed, helper methods still broken

Fixed:

• ✅ Line 1555: UpdateGhoulManagement() - Now accepts target parameter
• ✅ Line 1603: CommandGhoulIfNeeded() - Uses target parameter

Remaining Errors (need target parameter passed through):

• ❌ Line 1085: HandleEmergencySurvival() - Uses target without parameter
• ❌ Line 1182: UpdateCombatPhase() - Uses target without parameter
• ❌ Line 1185: UpdateCombatPhase() - Uses target without parameter
• ❌ Line 1212: UpdateCombatPhase() - Uses target without parameter (2x)

EvokerAI.cpp (FIXED ✅)

File: src/modules/Playerbot/AI/ClassAI/Evokers/EvokerAI.cpp

Status: COMPLETELY FIXED

• ✅ Line 656: UpdateEssenceManagement() - Now accepts target parameter

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3. QuestManager Systems (NOT FIXED ❌)

Execution Context: Called from BotAI::UpdateAI() → UpdateManagers() line 1826 Runs On: WORKER THREADS via thread pool Severity: CRITICAL - Quest operations are frequent

QuestCompletion.cpp (6 calls)

File: src/modules/Playerbot/Quest/QuestCompletion.cpp

Line 467:  Creature* creature = ObjectAccessor::GetCreature(*bot, guid);
Line 577:  Creature* creature = ObjectAccessor::GetCreature(*bot, guid);
Line 827:  auto* entity = ObjectAccessor::GetCreature(*bot, guid);
Line 902:  auto* entity = ObjectAccessor::GetCreature(*bot, guid);
Line 1003: auto* entity = ObjectAccessor::GetCreature(*bot, guid);
Line 1063: Creature* creature = ObjectAccessor::GetCreature(*bot, guid);

Context: Quest completion checks, turn-in validation, NPC interaction

QuestPickup.cpp (3 calls)

File: src/modules/Playerbot/Quest/QuestPickup.cpp

Line 242: Creature* creature = ObjectAccessor::GetCreature(*bot, ObjectGuid::Create<...>);
Line 248: GameObject* go = ObjectAccessor::GetGameObject(*bot, ObjectGuid::Create<...>);
Line 406: auto* entity = ObjectAccessor::GetCreature(*bot, guid);

Context: Quest giver detection, quest acceptance

QuestTurnIn.cpp (2 calls)

File: src/modules/Playerbot/Quest/QuestTurnIn.cpp

Line 400: Creature* creature = ObjectAccessor::GetCreature(*bot, guid);

Context: Quest turn-in NPC validation

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4. GatheringManager (NOT FIXED ❌)

Execution Context: Called from BotAI::UpdateAI() → UpdateManagers() line 1842 Runs On: WORKER THREADS via thread pool Severity: CRITICAL - Gathering operations are very frequent

GatheringManager.cpp (5 calls)

File: src/modules/Playerbot/Professions/GatheringManager.cpp

Line 242: target = ObjectAccessor::GetCreature(*GetBot(), node.guid);
          // In PerformGathering() - Skinning corpses

Line 260: GameObject* gameObject = ObjectAccessor::GetGameObject(*GetBot(), node.guid);
          // In PerformGathering() - Mining/Herbalism nodes

Line 604: Creature* creature = ObjectAccessor::GetCreature(*GetBot(), guid);
          // In ScanForSkinnableCorpses() - Finding skinnable mobs

Line 665: Creature* creature = ObjectAccessor::GetCreature(*GetBot(), node.guid);
          // In IsNodeValid() - Validating skinnable corpses

Line 670: GameObject* gameObject = ObjectAccessor::GetGameObject(*GetBot(), node.guid);
          // In IsNodeValid() - Validating gathering nodes

Context: Mining, Herbalism, Skinning - All professions that scan/interact with world objects

---

5. Strategy Systems (NOT FIXED ❌)

Execution Context: Strategies are executed during BotAI::UpdateAI() trigger processing Runs On: WORKER THREADS via thread pool Severity: HIGH - Combat/movement strategies run frequently

CombatMovementStrategy.cpp (1 call)

File: src/modules/Playerbot/AI/Strategy/CombatMovementStrategy.cpp

Line 417: Creature* creature = ObjectAccessor::GetCreature(*player, guid);

Context: Combat positioning, kiting, range management

LootStrategy.cpp (6 calls)

File: src/modules/Playerbot/AI/Strategy/LootStrategy.cpp

Line 286: Creature* creature = ObjectAccessor::GetCreature(*bot, corpseGuid);
          // Finding lootable corpses

Line 324: GameObject* object = ObjectAccessor::GetGameObject(*bot, objectGuid);
          // Finding lootable containers

Line 394: objA = ObjectAccessor::GetCreature(*bot, a);
          // Loot priority comparison

Line 396: objA = ObjectAccessor::GetGameObject(*bot, a);
          // Loot priority comparison

Line 399: objB = ObjectAccessor::GetCreature(*bot, b);
          // Loot priority comparison

Line 401: objB = ObjectAccessor::GetGameObject(*bot, b);
          // Loot priority comparison

Context: Loot scanning, priority calculation, corpse/container detection

QuestStrategy.cpp (3 calls)

File: src/modules/Playerbot/AI/Strategy/QuestStrategy.cpp

Line 875:  GameObject* go = ObjectAccessor::GetGameObject(*bot, ObjectGuid::Create<...>);
           // Quest objective interaction

Line 1375: ::Unit* target = ObjectAccessor::GetUnit(*bot, ObjectGuid::Create<...>);
           // Quest target validation

Line 1456: GameObject* gameObject = ObjectAccessor::GetGameObject(*bot, ObjectGuid::Create<...>);
           // Quest object interaction

Context: Quest objective tracking, interaction logic

---

DEADLOCK MECHANISM

How These Cause Deadlocks

1. BotAI::UpdateAI() runs on worker threads from thread pool
2. UpdateManagers() calls QuestManager, GatheringManager, etc. on worker threads
3. Strategy execution happens during trigger processing on worker threads
4. All ObjectAccessor::Get* methods access Map::_objectsStore
5. Map::_objectsStore is an unprotected std::unordered_map (NO MUTEXES)
6. Multiple worker threads accessing the same unprotected data structure → DEADLOCK

Why Futures 3-14 Never Complete

With 5000+ bots:

• Thousands of worker threads executing UpdateAI() simultaneously
• Each thread calling QuestManager, GatheringManager, and Strategies
• Each manager making 1-11 ObjectAccessor calls
• Total concurrent Map access: 5000 bots × ~20 calls = ~100,000 concurrent Map accesses
• Map has NO protection → undefined behavior → futures hang forever

---

FIX STRATEGY

Pattern (Based on Successful TargetScanner Fix)

BEFORE (DEADLOCK):

void SomeManager::Update(uint32 diff)
{
    // Running on worker thread!
    Creature* npc = ObjectAccessor::GetCreature(*bot, guid);  // DEADLOCK!
    if (npc)
        DoSomething(npc);
}

AFTER (THREAD-SAFE):

void SomeManager::Update(uint32 diff)
{
    // Running on worker thread!
    ObjectGuid npcGuid = FindNPC();  // Use spatial grid snapshots

    if (!npcGuid.IsEmpty())
    {
        // Queue action with GUID - main thread will resolve
        sBotActionMgr->QueueAction(BotAction::InteractNPC(
            bot->GetGUID(),
            npcGuid,
            getMSTime()
        ));
    }
}

Implementation Steps

1. QuestManager Systems (11 calls):

   • Change methods to work with GUIDs from spatial grid
   • Queue ACCEPT_QUEST/TURN_IN_QUEST/INTERACT_NPC actions
   • Main thread resolves GUIDs → pointers safely

2. GatheringManager (5 calls):

   • Change PerformGathering to accept GUID parameter
   • Change ScanForSkinnableCorpses to return GUIDs
   • Change IsNodeValid to accept GUID parameter
   • Queue INTERACT_OBJECT/LOOT_OBJECT actions

3. Strategy Systems (10 calls):

   • CombatMovementStrategy: Use position data from snapshots
   • LootStrategy: Return GUIDs, queue LOOT_OBJECT actions
   • QuestStrategy: Queue INTERACT_OBJECT/INTERACT_NPC actions

4. UnholySpecialization Helper Methods (5 remaining):

   • Pass target parameter through entire call chain
   • HandleEmergencySurvival(::Unit* target)
   • UpdateCombatPhase(::Unit* target)

---

PRIORITY ORDER

IMMEDIATE (Block Compilation):

1. ✅ Fix UnholySpecialization compilation errors (5 errors)

CRITICAL (High Frequency):

2. ❌ Fix GatheringManager (5 calls) - Runs every frame for gathering bots
3. ❌ Fix QuestManager (11 calls) - Runs every frame for questing bots

HIGH (Frequent):

4. ❌ Fix LootStrategy (6 calls) - Runs after every combat
5. ❌ Fix QuestStrategy (3 calls) - Runs during quest execution

MEDIUM:

6. ❌ Fix CombatMovementStrategy (1 call) - Combat positioning

---

EXPECTED RESULTS AFTER COMPLETE FIX

With ALL 31 ObjectAccessor Calls Eliminated:

✅ Zero Map access from worker threads ✅ 100% lock-free spatial grid queries ✅ All GUID resolution on main thread only ✅ Action queue handles all Map-touching operations

Testing Targets:

• Build succeeds (fix UnholySpecialization errors first)
• Spawn 100 bots - verify futures complete
• Spawn 1000 bots - verify futures complete
• Spawn 5000 bots - CRITICAL TEST: futures 3-14 MUST complete
• Monitor for 60-second hangs - MUST BE ZERO
• Verify quest operations work
• Verify gathering operations work
• Verify combat rotations work
• Check server logs for deadlock warnings

---

NEXT ACTIONS

1. Fix UnholySpecialization compilation errors (blocking build)
2. Create automated refactoring script for all 31 ObjectAccessor calls
3. Implement fixes system-by-system following TargetScanner pattern
4. Build and test with increasing bot counts (100 → 1000 → 5000)
5. Verify futures 3-14 complete with 5000+ bots

---

SUMMARY

CRITICAL DEADLOCK SOURCES IDENTIFIED: 31 ObjectAccessor calls from worker threads

SYSTEMS AFFECTED: Quest (11), Gathering (5), Loot (6), ClassAI (5), Quest Strategy (3), Combat Movement (1)

ROOT CAUSE: All managers run on worker threads via BotAI::UpdateAI() → UpdateManagers()

FIX PATTERN: Return GUIDs instead of pointers, queue actions, resolve on main thread

EXPECTED OUTCOME: 100% deadlock elimination, futures 3-14 complete with 5000+ bots