PaperMC/patches/server/0414-Fix-Chunk-Post-Processing-deadlock-risk.patch
Jason bc127ea819
Updated Upstream (Bukkit/CraftBukkit/Spigot) (#6222)
Upstream has released updates that appear to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

Bukkit Changes:
eec4aab0 SPIGOT-6657: Add getPlayer to SheepDyeWoolEvent
205213c6 SPIGOT-6656: CauldronLevelChangeEvent is not fired correctly when dripstone fills the cauldron

CraftBukkit Changes:
b8c522d5 SPIGOT-6657: Add getPlayer to SheepDyeWoolEvent
f04a77dc SPIGOT-6656: CauldronLevelChangeEvent is not fired correctly when dripstone fills the cauldron
d1dbcebc SPIGOT-6653: Canceling snow bucket placement removes snow from bucket
4f34a67b #891: Fix scheduler task ID overflow and duplication issues

Spigot Changes:
d03d7f12 BUILDTOOLS-604: Rebuild patches
2021-07-18 09:41:53 +02:00

59 lines
3.3 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 18 Apr 2020 04:36:11 -0400
Subject: [PATCH] Fix Chunk Post Processing deadlock risk
See: https://gist.github.com/aikar/dd22bbd2a3d78a2fd3d92e95e9f28dc6
as part of post processing a chunk, we can call ChunkConverter.
ChunkConverter then kicks off major physics updates, and when blocks
that have connections across chunk boundries occur, a recursive risk
can occur where A updates a block that triggers a physics request.
That physics request may trigger a chunk request, that then enqueues
a task into the Mailbox ChunkTaskQueueSorter.
If anything requests that same chunk that is in the middle of conversion,
it's mailbox queue is going to be held up, so the subsequent chunk request
will be unable to proceed.
We delay post processing of Chunk.A() 1 "pass" by re stuffing it back into
the executor so that the mailbox ChunkQueue is now considered empty.
This successfully fixed a reoccurring and highly reproduceable crash
for heightmaps.
diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index 6d810cdb538d078dbf7ccd2ef84a4be27eb1f3e7..aa9846c7d6b8499e01bf0ffeece6a940e0879328 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -195,6 +195,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
};
// CraftBukkit end
+ final CallbackExecutor chunkLoadConversionCallbackExecutor = new CallbackExecutor(); // Paper
// Paper start - distance maps
private final com.destroystokyo.paper.util.misc.PooledLinkedHashSets<ServerPlayer> pooledLinkedPlayerHashSets = new com.destroystokyo.paper.util.misc.PooledLinkedHashSets<>();
// Paper start - no-tick view distance
@@ -1091,7 +1092,7 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
return Either.left(chunk);
});
}, (runnable) -> {
- this.mainThreadMailbox.tell(ChunkTaskPriorityQueueSorter.message(holder, runnable));
+ this.mainThreadMailbox.tell(ChunkTaskPriorityQueueSorter.message(holder, () -> ChunkMap.this.chunkLoadConversionCallbackExecutor.execute(runnable))); // Paper - delay running Chunk post processing until outside of the sorter to prevent a deadlock scenario when post processing causes another chunk request.
});
completablefuture1.thenAcceptAsync((either) -> {
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index a376fa2456607337d3eec007abd5622a8d75ae42..e9ea16a953cff7c980cd0c1e5c2a4dcdada55f00 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -1009,6 +1009,7 @@ public class ServerChunkCache extends ChunkSource {
return super.pollTask() || execChunkTask; // Paper
}
} finally {
+ chunkMap.chunkLoadConversionCallbackExecutor.run(); // Paper - Add chunk load conversion callback executor to prevent deadlock due to recursion in the chunk task queue sorter
chunkMap.callbackExecutor.run();
}
// CraftBukkit end