Paper/patches/server/0492-Fix-for-large-move-vectors-crashing-server.patch
Spottedleaf 01a13871de
Rewrite chunk system (#8177)
Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.
2022-09-26 01:02:51 -07:00

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Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 17 May 2020 23:47:33 -0700
Subject: [PATCH] Fix for large move vectors crashing server
Check movement distance also based on current position.
diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index 214771e661ca3303af167fda3b623d83f0f63055..3d7d23a02e4aceb95ec36fbca9d02294f08c5780 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -575,9 +575,9 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
if (entity != this.player && entity.getControllingPassenger() == this.player && entity == this.lastVehicle) {
ServerLevel worldserver = this.player.getLevel();
- double d0 = entity.getX();
- double d1 = entity.getY();
- double d2 = entity.getZ();
+ double d0 = entity.getX();final double fromX = d0; // Paper - OBFHELPER
+ double d1 = entity.getY();final double fromY = d1; // Paper - OBFHELPER
+ double d2 = entity.getZ();final double fromZ = d2; // Paper - OBFHELPER
double d3 = ServerGamePacketListenerImpl.clampHorizontal(packet.getX()); final double toX = d3; // Paper - OBFHELPER
double d4 = ServerGamePacketListenerImpl.clampVertical(packet.getY()); final double toY = d4; // Paper - OBFHELPER
double d5 = ServerGamePacketListenerImpl.clampHorizontal(packet.getZ()); final double toZ = d5; // Paper - OBFHELPER
@@ -587,8 +587,19 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
double d7 = d4 - this.vehicleFirstGoodY;
double d8 = d5 - this.vehicleFirstGoodZ;
double d9 = entity.getDeltaMovement().lengthSqr();
- double d10 = d6 * d6 + d7 * d7 + d8 * d8;
-
+ // Paper start - fix large move vectors killing the server
+ double currDeltaX = toX - fromX;
+ double currDeltaY = toY - fromY;
+ double currDeltaZ = toZ - fromZ;
+ double d10 = Math.max(d6 * d6 + d7 * d7 + d8 * d8, (currDeltaX * currDeltaX + currDeltaY * currDeltaY + currDeltaZ * currDeltaZ) - 1);
+ // Paper end - fix large move vectors killing the server
+
+ // Paper start - fix large move vectors killing the server
+ double otherFieldX = d3 - this.vehicleLastGoodX;
+ double otherFieldY = d4 - this.vehicleLastGoodY - 1.0E-6D;
+ double otherFieldZ = d5 - this.vehicleLastGoodZ;
+ d10 = Math.max(d10, (otherFieldX * otherFieldX + otherFieldY * otherFieldY + otherFieldZ * otherFieldZ) - 1);
+ // Paper end - fix large move vectors killing the server
// CraftBukkit start - handle custom speeds and skipped ticks
this.allowedPlayerTicks += (System.currentTimeMillis() / 50) - this.lastTick;
@@ -634,9 +645,9 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
boolean flag = worldserver.noCollision(entity, entity.getBoundingBox().deflate(0.0625D));
- d6 = d3 - this.vehicleLastGoodX;
- d7 = d4 - this.vehicleLastGoodY - 1.0E-6D;
- d8 = d5 - this.vehicleLastGoodZ;
+ d6 = d3 - this.vehicleLastGoodX; // Paper - diff on change, used for checking large move vectors above
+ d7 = d4 - this.vehicleLastGoodY - 1.0E-6D; // Paper - diff on change, used for checking large move vectors above
+ d8 = d5 - this.vehicleLastGoodZ; // Paper - diff on change, used for checking large move vectors above
boolean flag1 = entity.verticalCollisionBelow;
entity.move(MoverType.PLAYER, new Vec3(d6, d7, d8));
@@ -1356,7 +1367,18 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
double d8 = d1 - this.firstGoodY;
double d9 = d2 - this.firstGoodZ;
double d10 = this.player.getDeltaMovement().lengthSqr();
- double d11 = d7 * d7 + d8 * d8 + d9 * d9;
+ // Paper start - fix large move vectors killing the server
+ double currDeltaX = toX - prevX;
+ double currDeltaY = toY - prevY;
+ double currDeltaZ = toZ - prevZ;
+ double d11 = Math.max(d7 * d7 + d8 * d8 + d9 * d9, (currDeltaX * currDeltaX + currDeltaY * currDeltaY + currDeltaZ * currDeltaZ) - 1);
+ // Paper end - fix large move vectors killing the server
+ // Paper start - fix large move vectors killing the server
+ double otherFieldX = d0 - this.lastGoodX;
+ double otherFieldY = d1 - this.lastGoodY;
+ double otherFieldZ = d2 - this.lastGoodZ;
+ d11 = Math.max(d11, (otherFieldX * otherFieldX + otherFieldY * otherFieldY + otherFieldZ * otherFieldZ) - 1);
+ // Paper end - fix large move vectors killing the server
if (this.player.isSleeping()) {
if (d11 > 1.0D) {
@@ -1408,9 +1430,9 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Tic
AABB axisalignedbb = this.player.getBoundingBox();
- d7 = d0 - this.lastGoodX;
- d8 = d1 - this.lastGoodY;
- d9 = d2 - this.lastGoodZ;
+ d7 = d0 - this.lastGoodX; // Paper - diff on change, used for checking large move vectors above
+ d8 = d1 - this.lastGoodY; // Paper - diff on change, used for checking large move vectors above
+ d9 = d2 - this.lastGoodZ; // Paper - diff on change, used for checking large move vectors above
boolean flag = d8 > 0.0D;
if (this.player.isOnGround() && !packet.isOnGround() && flag) {