papermc/Spigot-Server-Patches/0453-Prevent-Double-PlayerChunkMap-adds-crashing-server.patch
Aikar f37381ea8a
Optimize Network Manager to not need synchronization
Removes synchronization from sending packets
Makes normal packet sends no longer need to be wrapped and queued like it use to work.
Adds more packet queue immunities on top of keep alive to let the following scenarios go out
without delay:
  - Keep Alive
  - Chat
  - Kick
  - All of the packets during the Player Joined World event

Hoping that latter one helps join timeout issues more too for slow connections.

Removes processing packet queue off of main thread
  - for the few cases where it is allowed, order is not necessary nor
    should it even be happening concurrently in first place (handshaking/login/status)

Ensures packets sent asynchronously are dispatched on main thread

This helps ensure safety for ProtocolLib as packet listeners
are commonly accessing world state. This will allow you to schedule
a packet to be sent async, but itll be dispatched sync for packet
listeners to process.

This should solve some deadlock risks

This may provide a decent performance improvement because thread synchronization incurs a cache reset
so by avoiding ever entering a synchronized block, we get to avoid that, and packet sending is a really
hot activity.
2020-05-06 05:28:47 -04:00

51 lines
2.8 KiB
Diff

From 3bf2d6906af2ae65a709444f3d72597ead34cac1 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 2 Apr 2020 01:42:39 -0400
Subject: [PATCH] Prevent Double PlayerChunkMap adds crashing server
Suspected case would be around the technique used in .stopRiding
Stack will identify any causer of this and warn instead of crashing.
diff --git a/src/main/java/net/minecraft/server/PlayerChunkMap.java b/src/main/java/net/minecraft/server/PlayerChunkMap.java
index 6eb05591317..4beae504c87 100644
--- a/src/main/java/net/minecraft/server/PlayerChunkMap.java
+++ b/src/main/java/net/minecraft/server/PlayerChunkMap.java
@@ -1446,6 +1446,14 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
protected void addEntity(Entity entity) {
org.spigotmc.AsyncCatcher.catchOp("entity track"); // Spigot
+ // Paper start - ignore and warn about illegal addEntity calls instead of crashing server
+ if (!entity.valid || entity.world != this.world || this.trackedEntities.containsKey(entity.getId())) {
+ new Throwable("[ERROR] Illegal PlayerChunkMap::addEntity for world " + this.world.getWorld().getName()
+ + ": " + entity + (this.trackedEntities.containsKey(entity.getId()) ? " ALREADY CONTAINED (This would have crashed your server)" : ""))
+ .printStackTrace();
+ return;
+ }
+ // Paper end
if (!(entity instanceof EntityComplexPart)) {
if (!(entity instanceof EntityLightning)) {
EntityTypes<?> entitytypes = entity.getEntityType();
diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
index 9fbe8fa1b2b..2a7a47c6707 100644
--- a/src/main/java/net/minecraft/server/WorldServer.java
+++ b/src/main/java/net/minecraft/server/WorldServer.java
@@ -1472,7 +1472,7 @@ public class WorldServer extends World {
}
}
- this.getChunkProvider().addEntity(entity);
+ // this.getChunkProvider().addEntity(entity); // Paper - moved down below valid=true
// CraftBukkit start - SPIGOT-5278
if (entity instanceof EntityDrowned) {
this.navigators.add(((EntityDrowned) entity).navigationWater);
@@ -1483,6 +1483,7 @@ public class WorldServer extends World {
this.navigators.add(((EntityInsentient) entity).getNavigation());
}
entity.valid = true; // CraftBukkit
+ this.getChunkProvider().addEntity(entity); // Paper - from above to be below valid=true
// Paper start - Set origin location when the entity is being added to the world
if (entity.origin == null) {
entity.origin = entity.getBukkitEntity().getLocation();
--
2.26.2