Minecraft Version

Other (specify below)

Mod Loader

Forge

Mod Loader Version

Forge 47.3.0

Mod Version

1.20-14.1.4

Balm Version

1.20.1-7.3.7-all

Describe the Issue

Every hour or so when someone uses a waystone, the server will crash and restart. I've noticed that this occurs most frequently when using Waystones between dimensions. Everytime it happens, the crash report shows a java.util.ConcurrentModificationException: null error. Here is the full crash report:

---- Minecraft Crash Report ----
// Everything's going to plan. No, really, that was supposed to happen.

Time: 2024-08-14 22:57:50
Description: Exception in server tick loop

java.util.ConcurrentModificationException: null
at java.util.HashMap$HashIterator.nextNode(HashMap.java:1597) ~[?:?] {}
at java.util.HashMap$KeyIterator.next(HashMap.java:1620) ~[?:?] {}
at java.lang.Iterable.forEach(Iterable.java:74) ~[?:?] {re:mixin}
at net.minecraft.server.level.DistanceManager.m_140805_(DistanceManager.java:119) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:classloading}
at net.minecraft.server.level.ServerChunkCache.m_8489_(ServerChunkCache.java:273) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:cupboard.mixins.json:ChunkLoadDebug,pl:mixin:A}
at net.minecraft.server.level.ServerChunkCache$MainThreadExecutor.m_7245_(ServerChunkCache.java:545) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:classloading}
at net.minecraft.server.level.ServerChunkCache.m_8466_(ServerChunkCache.java:269) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:cupboard.mixins.json:ChunkLoadDebug,pl:mixin:A}
at net.minecraft.server.MinecraftServer.m_129961_(MinecraftServer.java:758) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:unionlib.mixins.json:MinecraftServerMixin,pl:mixin:APP:citadel.mixins.json:MinecraftServerMixin,pl:mixin:APP:balm.mixins.json:MinecraftServerMixin,pl:mixin:A}
at net.minecraft.server.MinecraftServer.m_7245_(MinecraftServer.java:747) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:unionlib.mixins.json:MinecraftServerMixin,pl:mixin:APP:citadel.mixins.json:MinecraftServerMixin,pl:mixin:APP:balm.mixins.json:MinecraftServerMixin,pl:mixin:A}
at net.minecraft.util.thread.BlockableEventLoop.m_18701_(BlockableEventLoop.java:139) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:computing_frames,pl:accesstransformer:B,re:mixin,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.m_130012_(MinecraftServer.java:733) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:unionlib.mixins.json:MinecraftServerMixin,pl:mixin:APP:citadel.mixins.json:MinecraftServerMixin,pl:mixin:APP:balm.mixins.json:MinecraftServerMixin,pl:mixin:A}
at net.minecraft.server.MinecraftServer.m_130011_(MinecraftServer.java:665) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:unionlib.mixins.json:MinecraftServerMixin,pl:mixin:APP:citadel.mixins.json:MinecraftServerMixin,pl:mixin:APP:balm.mixins.json:MinecraftServerMixin,pl:mixin:A}
at net.minecraft.server.MinecraftServer.m_206580_(MinecraftServer.java:251) ~[server-1.20.1-20230612.114412-srg.jar%23207!/:?] {re:mixin,pl:accesstransformer:B,re:computing_frames,pl:accesstransformer:B,re:classloading,pl:accesstransformer:B,pl:mixin:APP:unionlib.mixins.json:MinecraftServerMixin,pl:mixin:APP:citadel.mixins.json:MinecraftServerMixin,pl:mixin:APP:balm.mixins.json:MinecraftServerMixin,pl:mixin:A}
at java.lang.Thread.run(Thread.java:840) ~[?:?] {re:mixin}

A detailed walkthrough of the error, its code path and all known details is as follows:

-- System Details --
Details:
Minecraft Version: 1.20.1
Minecraft Version ID: 1.20.1
Operating System: Linux (amd64) version 5.4.0-121-generic
Java Version: 17.0.12, Eclipse Adoptium
Java VM Version: OpenJDK 64-Bit Server VM (mixed mode, sharing), Eclipse Adoptium
Memory: 1513343456 bytes (1443 MiB) / 3472883712 bytes (3312 MiB) up to 21944598528 bytes (20928 MiB)
CPUs: 32
Processor Vendor: GenuineIntel
Processor Name: Intel(R) Xeon(R) CPU E5-2667 v3 @ 3.20GHz
Identifier: Intel64 Family 6 Model 63 Stepping 2
Microarchitecture: Haswell (Server)
Frequency (GHz): 3.20
Number of physical packages: 2
Number of physical CPUs: 16
Number of logical CPUs: 32
Graphics card #0 name: unknown
Graphics card #0 vendor: unknown
Graphics card #0 VRAM (MB): 0.00
Graphics card #0 deviceId: unknown
Graphics card #0 versionInfo: unknown
Virtual memory max (MB): 178062.06
Virtual memory used (MB): 198876.16
Swap memory total (MB): 49151.99
Swap memory used (MB): 30168.97
JVM Flags: 21 total; -XX:SurvivorRatio=32 -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -XX:G1NewSizePercent=40 -XX:G1MaxNewSizePercent=50 -XX:G1HeapRegionSize=16M -XX:G1ReservePercent=15 -XX:+UseContainerSupport -Xms128M -XX:MaxRAMPercentage=85
Server Running: true
Player Count: 3 / 20; [ServerPlayer['nuxn'/33, l='ServerLevel[world]', x=47.40, y=64.53, z=-17.32], ServerPlayer['1pple'/2480, l='ServerLevel[world]', x=-14822.83, y=-1.91, z=4252.44], ServerPlayer['aylixo'/5420, l='ServerLevel[world]', x=-14820.13, y=-5.37, z=4255.98]]
Data Packs: vanilla, mod:betterdungeons, mod:kuma_api (incompatible), mod:unionlib (incompatible), mod:betterwitchhuts, mod:aether, mod:jei, mod:betteroceanmonuments, mod:libraryferret, mod:mcwwindows, mod:waystones, mod:journeymap (incompatible), mod:citadel (incompatible), mod:alexsmobs (incompatible), mod:travelersbackpack, mod:yungsapi, mod:mixinextras (incompatible), mod:betterdeserttemples, mod:mcwdoors, mod:ironshulkerbox, mod:balm, mod:terralith, mod:betterfortresses, mod:forge, mod:twilightforest, mod:konkrete (incompatible), mod:ironchest, mod:corpse, mod:farmersdelight, mod:handcrafted (incompatible), mod:terrablender, mod:mousetweaks, mod:biomesoplenty (incompatible), mod:ironfurnaces, mod:mcwtrpdoors, mod:mcwfences, mod:betterfpsdist (incompatible), mod:notenoughanimations, mod:curios (incompatible), mod:bettervillage, mod:betterstrongholds, mod:resourcefullib (incompatible), mod:cumulus_menus, mod:structory_towers, mod:architectury (incompatible), mod:doapi (incompatible), mod:bakery (incompatible), mod:moremobvariants, mod:mcwfurnitures, mod:cupboard (incompatible), mod:mvw, mod:betterendisland, mod:justzoom (incompatible), mod:nitrogen_internals, mod:mavapi (incompatible), mod:mavm (incompatible), mod:bettermineshafts, mod:betterjungletemples, builtin/aether_accessories, minecraft_bricks, mod:dimension_access_manager, mod:antixray
Enabled Feature Flags: minecraft:vanilla
World Generation: Stable
Is Modded: Definitely; Server brand changed to 'forge'
Type: Dedicated Server (map_server.txt)
ModLauncher: 10.0.9+10.0.9+main.dcd20f30
ModLauncher launch target: forgeserver
ModLauncher naming: srg
ModLauncher services:
mixin-0.8.5.jar mixin PLUGINSERVICE
eventbus-6.0.5.jar eventbus PLUGINSERVICE
fmlloader-1.20.1-47.3.0.jar slf4jfixer PLUGINSERVICE
fmlloader-1.20.1-47.3.0.jar object_holder_definalize PLUGINSERVICE
fmlloader-1.20.1-47.3.0.jar runtime_enum_extender PLUGINSERVICE
fmlloader-1.20.1-47.3.0.jar capability_token_subclass PLUGINSERVICE
accesstransformers-8.0.4.jar accesstransformer PLUGINSERVICE
fmlloader-1.20.1-47.3.0.jar runtimedistcleaner PLUGINSERVICE
modlauncher-10.0.9.jar mixin TRANSFORMATIONSERVICE
modlauncher-10.0.9.jar fml TRANSFORMATIONSERVICE
FML Language Providers:
[email protected]
lowcodefml@null
javafml@null
Mod List:
YungsBetterDungeons-1.20-Forge-4.0.4.jar |YUNG's Better Dungeons |betterdungeons |1.20-Forge-4.0.4 |DONE |Manifest: NOSIGNATURE
kuma-api-forge-20.1.8+1.20.1.jar |KumaAPI |kuma_api |20.1.8 |DONE |Manifest: NOSIGNATURE
UnionLib-1.20.1-10.2.6-Forge.jar |UnionLib |unionlib |10.2.6 |DONE |Manifest: NOSIGNATURE
YungsBetterWitchHuts-1.20-Forge-3.0.3.jar |YUNG's Better Witch Huts |betterwitchhuts |1.20-Forge-3.0.3 |DONE |Manifest: NOSIGNATURE
aether-1.20.1-1.4.2-neoforge.jar |The Aether |aether |1.20.1-1.4.2-neoforg|DONE |Manifest: NOSIGNATURE
jei-1.20.1-forge-15.12.3.53.jar |Just Enough Items |jei |15.12.3.53 |DONE |Manifest: NOSIGNATURE
YungsBetterOceanMonuments-1.20-Forge-3.0.4.jar |YUNG's Better Ocean Monuments |betteroceanmonuments |1.20-Forge-3.0.4 |DONE |Manifest: NOSIGNATURE
libraryferret-forge-1.20.1-4.0.0.jar |Library ferret |libraryferret |4.0.0 |DONE |Manifest: NOSIGNATURE
mcw-windows-2.3.0-mc1.20.1forge.jar |Macaw's Windows |mcwwindows |2.3.0 |DONE |Manifest: NOSIGNATURE
waystones-forge-1.20-14.1.4.jar |Waystones |waystones |14.1.4 |DONE |Manifest: NOSIGNATURE
journeymap-1.20.1-5.10.1-forge.jar |Journeymap |journeymap |5.10.1 |DONE |Manifest: NOSIGNATURE
citadel-2.5.7-1.20.1.jar |Citadel |citadel |2.5.7 |DONE |Manifest: NOSIGNATURE
alexsmobs-1.22.8.jar |Alex's Mobs |alexsmobs |1.22.8 |DONE |Manifest: NOSIGNATURE
travelersbackpack-forge-1.20.1-9.1.15.jar |Traveler's Backpack |travelersbackpack |9.1.15 |DONE |Manifest: NOSIGNATURE
YungsApi-1.20-Forge-4.0.5.jar |YUNG's API |yungsapi |1.20-Forge-4.0.5 |DONE |Manifest: NOSIGNATURE
mixinextras-forge-0.2.0-beta.9.jar |MixinExtras |mixinextras |0.2.0-beta.9 |DONE |Manifest: NOSIGNATURE
anti-xray-1.3.1-Forge-1.20.1.jar |AntiXray |antixray |1.3.1 |DONE |Manifest: NOSIGNATURE
YungsBetterDesertTemples-1.20-Forge-3.0.3.jar |YUNG's Better Desert Temples |betterdeserttemples |1.20-Forge-3.0.3 |DONE |Manifest: NOSIGNATURE
mcw-doors-1.1.1forge-mc1.20.1.jar |Macaw's Doors |mcwdoors |1.1.1 |DONE |Manifest: NOSIGNATURE
ironshulkerbox-1.20.1-5.3.2.jar |Iron Shulker Boxes |ironshulkerbox |1.20.1-5.3.2 |DONE |Manifest: NOSIGNATURE
balm-forge-1.20.1-7.3.7-all.jar |Balm |balm |7.3.7 |DONE |Manifest: NOSIGNATURE
Terralith_1.20.x_v2.5.4.jar |Terralith |terralith |2.5.4 |DONE |Manifest: NOSIGNATURE
YungsBetterNetherFortresses-1.20-Forge-2.0.6.jar |YUNG's Better Nether Fortresse|betterfortresses |1.20-Forge-2.0.6 |DONE |Manifest: NOSIGNATURE
forge-1.20.1-47.3.0-universal.jar |Forge |forge |47.3.0 |DONE |Manifest: 84:ce:76:e8:45:35:e4:0e:63:86:df:47:59:80:0f:67:6c:c1:5f:6e:5f:4d:b3:54:47:1a:9f:7f:ed:5e:f2:90
twilightforest-1.20.1-4.3.2508-universal.jar |The Twilight Forest |twilightforest |4.3.2508 |DONE |Manifest: NOSIGNATURE
konkrete_forge_1.8.0_MC_1.20-1.20.1.jar |Konkrete |konkrete |1.8.0 |DONE |Manifest: NOSIGNATURE
ironchest-1.20.1-14.4.4.jar |Iron Chests |ironchest |1.20.1-14.4.4 |DONE |Manifest: NOSIGNATURE
corpse-forge-1.20.1-1.0.12.jar |Corpse |corpse |1.20.1-1.0.12 |DONE |Manifest: NOSIGNATURE
server-1.20.1-20230612.114412-srg.jar |Minecraft |minecraft |1.20.1 |DONE |Manifest: NOSIGNATURE
FarmersDelight-1.20.1-1.2.4.jar |Farmer's Delight |farmersdelight |1.20.1-1.2.4 |DONE |Manifest: NOSIGNATURE
handcrafted-forge-1.20.1-3.0.6.jar |Handcrafted |handcrafted |3.0.6 |DONE |Manifest: NOSIGNATURE
TerraBlender-forge-1.20.1-3.0.1.7.jar |TerraBlender |terrablender |3.0.1.7 |DONE |Manifest: NOSIGNATURE
MouseTweaks-forge-mc1.20.1-2.25.1.jar |Mouse Tweaks |mousetweaks |2.25.1 |DONE |Manifest: NOSIGNATURE
BiomesOPlenty-1.20.1-18.0.0.592.jar |Biomes O' Plenty |biomesoplenty |18.0.0.592 |DONE |Manifest: NOSIGNATURE
ironfurnaces-1.20.1-4.1.6.jar |Iron Furnaces |ironfurnaces |4.1.6 |DONE |Manifest: NOSIGNATURE
mcw-trapdoors-1.1.3-mc1.20.1forge.jar |Macaw's Trapdoors |mcwtrpdoors |1.1.3 |DONE |Manifest: NOSIGNATURE
mcw-fences-1.1.2-mc1.20.1forge.jar |Macaw's Fences and Walls |mcwfences |1.1.2 |DONE |Manifest: NOSIGNATURE
DimensionAccessManager-1.20.1-3.1.0.jar |Dimension Access Manager |dimension_access_manager |3.1.0 |DONE |Manifest: NOSIGNATURE
betterfpsdist-1.20.1-4.4.jar |betterfpsdist mod |betterfpsdist |1.20.1-4.4 |DONE |Manifest: NOSIGNATURE
notenoughanimations-forge-1.7.4-mc1.20.1.jar |NotEnoughAnimations |notenoughanimations |1.7.4 |DONE |Manifest: NOSIGNATURE
curios-forge-5.3.5+1.20.1.jar |Curios API |curios |5.3.5+1.20.1 |DONE |Manifest: NOSIGNATURE
bettervillage-forge-1.20.1-3.2.0.jar |Better village |bettervillage |3.1.0 |DONE |Manifest: NOSIGNATURE
YungsBetterStrongholds-1.20-Forge-4.0.3.jar |YUNG's Better Strongholds |betterstrongholds |1.20-Forge-4.0.3 |DONE |Manifest: NOSIGNATURE
resourcefullib-forge-1.20.1-2.1.28.jar |Resourceful Lib |resourcefullib |2.1.28 |DONE |Manifest: NOSIGNATURE
cumulus_menus-1.20.1-1.0.0-neoforge.jar |Cumulus |cumulus_menus |1.20.1-1.0.0-neoforg|DONE |Manifest: NOSIGNATURE
Structory_Towers_1.20.x_v1.0.7.jar |Structory: Towers |structory_towers |1.0.7 |DONE |Manifest: NOSIGNATURE
architectury-9.2.14-forge.jar |Architectury |architectury |9.2.14 |DONE |Manifest: NOSIGNATURE
letsdo-API-forge-1.2.15-forge.jar |[Let's Do] API |doapi |1.2.15 |DONE |Manifest: NOSIGNATURE
letsdo-bakery-forge-1.1.15.jar |[Let's Do] Bakery |bakery |1.1.15 |DONE |Manifest: NOSIGNATURE
moremobvariants-forge+1.20.1-1.3.0.1.jar |More Mob Variants |moremobvariants |1.3.0.1 |DONE |Manifest: NOSIGNATURE
mcw-furniture-3.3.0-mc1.20.1forge.jar |Macaw's Furniture |mcwfurnitures |3.3.0 |DONE |Manifest: NOSIGNATURE
cupboard-1.20.1-2.7.jar |Cupboard utilities |cupboard |1.20.1-2.7 |DONE |Manifest: NOSIGNATURE
mvw-2.3.3b.jar |MoreVanillaWeapons |mvw |2.3.3b |DONE |Manifest: NOSIGNATURE
YungsBetterEndIsland-1.20-Forge-2.0.6.jar |YUNG's Better End Island |betterendisland |1.20-Forge-2.0.6 |DONE |Manifest: NOSIGNATURE
justzoom_forge_2.0.0_MC_1.20.1.jar |Just Zoom |justzoom |2.0.0 |DONE |Manifest: NOSIGNATURE
nitrogen_internals-1.20.1-1.0.7-neoforge.jar |Nitrogen |nitrogen_internals |1.20.1-1.0.7-neoforg|DONE |Manifest: NOSIGNATURE
mavapi-1.1.4-mc1.20.1.jar |More Axolotl Variants API |mavapi |1.1.4 |DONE |Manifest: NOSIGNATURE
mavm-1.2.6-mc1.20.1.jar |More Axolotl Variants Mod |mavm |1.2.6 |DONE |Manifest: NOSIGNATURE
YungsBetterMineshafts-1.20-Forge-4.0.4.jar |YUNG's Better Mineshafts |bettermineshafts |1.20-Forge-4.0.4 |DONE |Manifest: NOSIGNATURE
YungsBetterJungleTemples-1.20-Forge-2.0.5.jar |YUNG's Better Jungle Temples |betterjungletemples |1.20-Forge-2.0.5 |DONE |Manifest: NOSIGNATURE
Crash Report UUID: 76a6b956-b176-4a30-aa6c-b778d2d78aae
FML: 47.3
Forge: net.minecraftforge:47.3.0

Logs

No response

Do you use any performance-enhancing mods (e.g. OptiFine) or custom server distributions (e.g. SpongeForge)?

Most people in the server are using optifine on their clients

I don't see anything related to Waystones in that log.

Most likely something like this would be caused by mods that alter chunk loading (such as multithreading performance mods) or world generation.

Why does it only occur when using a waystone? It's happened less frequently as of lately, but still happens from time to time. Especially for users with lower end machines or bad internet connections.

Because waystones initiate a teleport which means chunks get loaded and unloaded and entities get moved around.

Closing for now until it can be narrowed down with which mod in particular it's occurring, since there hasn't been any reports of this happening with only Waystones installed.