server/onesync: fix deadlock caused by accidental recursive acquisition of a SRW lock

Author: blattersturm

code/components/citizen-server-impl/src/state/ServerGameState.cpp

@@ -1291,19 +1291,20 @@ void ServerGameState::HandleClientDrop(const std::shared_ptr<fx::Client>& client
 		}
 
 		{
-			std::shared_lock<std::shared_mutex> lock(m_entitiesByIdMutex);
-
-			auto entity = m_entitiesById[set & 0xFFFF];
+			std::weak_ptr<sync::SyncEntityState> entity;
 
 			{
+				std::shared_lock<std::shared_mutex> lock(m_entitiesByIdMutex);
+				entity = m_entitiesById[set & 0xFFFF];
+			}
+
 			auto entityRef = entity.lock();
 
 			if (entityRef)
 			{
 				OnCloneRemove(entityRef);
 			}
 		}
-		}
 
 		{
 			std::unique_lock<std::shared_mutex> entityListLock(m_entityListMutex);
@@ -1867,6 +1868,7 @@ void ServerGameState::AttachToObject(fx::ServerInstanceBase* instance)
 			auto [data, lock] = GetClientData(this, client);
 			int used = 0;
 
+			{
 				std::shared_lock<std::shared_mutex> entityListLock(m_entitiesByIdMutex);
 
 				for (auto object : data->objectIds)
@@ -1876,6 +1878,7 @@ void ServerGameState::AttachToObject(fx::ServerInstanceBase* instance)
 						used++;
 					}
 				}
+			}
 
 			console::Printf("net", "%s^7: %d/%d object IDs used/sent (%.2f percent)\n", client->GetName(), used, data->objectIds.size(), (used / (float)data->objectIds.size()) * 100.0f);
 		});