[1.21.11] EndDragonFight Deadlock

[PureGero]

How does this get deadlocked?

while (!this.level.chunkScheduler.getRegionLocker().tryLockNow(RegionPos.forChunk(0, 0), r)) {

Previous attempt at fix: 7a34f3e

Deadlock logs from 1.20.6:

[21:33:14] [Watchdog Thread/ERROR]: ------------------------------
[21:33:14] [Watchdog Thread/ERROR]: Server thread dump (Look for plugins here before reporting to ShreddedPaper!):
[21:33:14] [Watchdog Thread/ERROR]: ------------------------------
[21:33:14] [Watchdog Thread/ERROR]: Current Thread: Server thread
[21:33:14] [Watchdog Thread/ERROR]: 	PID: 81 | Suspended: false | Native: false | State: TIMED_WAITING
[21:33:14] [Watchdog Thread/ERROR]: 	Stack:
[21:33:14] [Watchdog Thread/ERROR]: 		java.base@21.0.9/jdk.internal.misc.Unsafe.park(Native Method)
[21:33:14] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.util.thread.BlockableEventLoop.waitForTasks(BlockableEventLoop.java:154)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.server.MinecraftServer.waitForTasks(MinecraftServer.java:1434)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:144)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1872)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.server.dedicated.DedicatedServer.tickChildren(DedicatedServer.java:509)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1621)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1272)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:333)
[21:33:14] [Watchdog Thread/ERROR]: 		net.minecraft.server.MinecraftServer$$Lambda/0x00007ef617ccbce8.run(Unknown Source)
[21:33:14] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.lang.Thread.runWith(Unknown Source)
[21:33:14] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.lang.Thread.run(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: ------------------------------
[21:33:20] [Watchdog Thread/ERROR]: Current Thread: ShreddedPaperTickThread-28
[21:33:20] [Watchdog Thread/ERROR]: 	PID: 240 | Suspended: false | Native: false | State: TIMED_WAITING
[21:33:20] [Watchdog Thread/ERROR]: 	Stack:
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/jdk.internal.misc.Unsafe.park(Native Method)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		net.minecraft.util.thread.BlockableEventLoop.waitForTasks(BlockableEventLoop.java:154)
[21:33:20] [Watchdog Thread/ERROR]: 		net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:144)
[21:33:20] [Watchdog Thread/ERROR]: 		net.minecraft.world.level.dimension.end.EndDragonFight.tick(EndDragonFight.java:188)
[21:33:20] [Watchdog Thread/ERROR]: 		net.minecraft.server.level.ServerLevel.lambda$tick$12(ServerLevel.java:922)
[21:33:20] [Watchdog Thread/ERROR]: 		net.minecraft.server.level.ServerLevel$$Lambda/0x00007ef619242c10.run(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.util.concurrent.CompletableFuture$UniRun.tryFire(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.util.concurrent.CompletableFuture.postComplete(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.util.concurrent.CompletableFuture$AsyncRun.run(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.lang.Thread.runWith(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: 		java.base@21.0.9/java.lang.Thread.run(Unknown Source)
[21:33:20] [Watchdog Thread/ERROR]: ------------------------------

[DaWHeL]

Im experiencing this exact same deadlock on version 1.20.6-161. The server hangs completely with the same stack trace pointing to EndDragonFight.tick Here is my log.