ModernFix causing frequent server crashes

[SageofTurtles]

Bug Description

Our server has been experiencing repeated crashes over the last week, which (after extensive testing) seem to be resolved only by removing ModernFix from our modpack. Possibly an incompatibility with another mod, but I'm having a lot of difficulty reproducing the issue, so I can't give too much information for this. There are a few different errors given in the crash reports/logs when this happens, but they all seem very similar, which leads me to believe the attached crash reports were all triggered by the same issue. We've done numerous tests on the one repeatable instance we were able to isolate (despite not knowing what was causing the crashes even in that instance) using versions 5.19.0, 5.18.10, 5.18.6, and 5.18.0 of your mod for Fabric 1.20.1, but every tested version seems to cause this same error. Only by removing ModernFix were we able to perform our test case without a server crash.

Reproduction Steps

I genuinely have no clue. Our test case was one of our players placing a row of soul sand in a certain area of his base in the world. We caught the crashes happening while he was doing this, and saved a backup of the world to perform troubleshooting on. Once we isolated and removed ModernFix, the crashes no longer occurred, and we removed the mod from our main server. This issue hasn't occurred in the 12 hours since that time, so I'm fairly confident that fixed it. But again, I could never find what exactly was triggering this to happen, only that it occurred in one specific case and did not occur when the mod was removed.

Log File

Here are the crash reports for our server from the last week that seem to be related to this issue, as best I am able to determine. The folder contains 32 of these crash reports. I'm happy to provide any additional details I possibly can.

Crash Reports.zip

[embeddedt]

Have you tried to reproduce this without C2ME? This looks like another mod changing entity chunk statuses on the wrong thread (which would lead to random exceptions from fastutil). I am not sure that ModernFix is actually causing the issue; it might just speed up some server process enough to make the crash happen more consistently. I also tried debugging locally with just ModernFix, and could not recreate a situation in which the crash would be possible.

[SageofTurtles]

C2ME was one of the first mods I tried removing, and the issue still occurred without it. I do recognize the possibility that this is actually caused by something else, ModernFix was just the only catalyst for this type of crash that I could find by trail-and-error.

[embeddedt]

What happens if mixin.bugfix.paper_chunk_patches is disabled in the ModernFix config?

[VanillaChan6571]

Can Confirm. Just crashes/hangs for no reason and basically never recovers. It seems to dislike datapacks. If you get the message below.

[ModernFix integrated server watchdog/ERROR]: A single server tick has taken 40001, more than 40000 milliseconds

Then your client is softlocked and needs to Alt + F4.

[FireDragon91245]

Also having the same issue on 1.19.2 Forge

Sometimes on World gen or normal server Oprations server crashes

client same modpack seems to work fine

[Numilani]

Also experiencing this issue, albeit I've done little-to-no testing to determine what mods seem to be clashing or what settings might fix it.

Was able to consistently reproduce the problem, though - flying over a specific section of terrain would apparently cause worldgen to lag out, the server watchdog would hit 40001 ms and crash, the world file wouldn't save, then loading the same file up would cause the same problem. Managed to crash the world three times in a row with the same problem, then tried removing ModernFix - no crashes.

Instance details below, excluding a modlist (I can pastebin that upon request):

Game Version: 1.20.1
Loader: Forge
Loader Version: 47.3.11
ModernFix Version: 5.19.4+mc1.20.1

Upon request, I'm happy to provide any information I can - I'd love to see this resolved, the performance of my pack is notably suffering without ModernFix.

[embeddedt]

Can you provide the log file when the watchdog kills it? That sounds like a different class of issue from what others here are experiencing, and probably easier to resolve.

[Numilani]

Sure, here's one example:

2024-10-13-3.log.gz

[vizthex123]

Got the same server tick message after running /reload on my 1.18.2 pack. I edited a KubeJS and CraftTweaker script, and didn't want to reload the entire game.
latest.log

[Minebrah]

I got the same problem on the latest release for Forge 1.20.1.

[embeddedt]

@Numilani Your issue appears to be a deadlock caused by In Control.

"Server thread" prio=4 Id=141 TIMED_WAITING on java.lang.String@2e2e6540
	at [email protected]/jdk.internal.misc.Unsafe.park(Native Method)
	-  waiting on java.lang.String@2e2e6540
	at [email protected]/java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:269)
	at TRANSFORMER/[email protected]/net.minecraft.util.thread.BlockableEventLoop.m_5667_(BlockableEventLoop.java:521)
	at TRANSFORMER/[email protected]/net.minecraft.util.thread.BlockableEventLoop.m_18701_(BlockableEventLoop.java:141)
	at TRANSFORMER/[email protected]/net.minecraft.server.level.ServerChunkCache.getChunkBlocking(ServerChunkCache.java:1768)
	at TRANSFORMER/[email protected]/net.minecraft.server.level.ServerChunkCache.m_7587_(ServerChunkCache.java:1664)
	at TRANSFORMER/[email protected]/net.minecraft.world.level.Level.m_6522_(Level.java:187)
	at TRANSFORMER/[email protected]/net.minecraft.world.level.Level.m_6325_(Level.java:4051)
	at TRANSFORMER/[email protected]/net.minecraft.world.level.Level.m_8055_(Level.java:4540)
	at TRANSFORMER/[email protected]/net.minecraft.world.level.LevelReader.m_46861_(LevelReader.java:97)
	at TRANSFORMER/[email protected]/mcjty.incontrol.rules.support.GenericRuleEvaluator.lambda$addSeeSkyCheck$35(GenericRuleEvaluator.java:394)
	at TRANSFORMER/[email protected]/mcjty.incontrol.rules.support.GenericRuleEvaluator$$Lambda/0x0000000083b10f50.apply(Unknown Source)
	at TRANSFORMER/[email protected]/mcjty.incontrol.rules.support.GenericRuleEvaluator.match(GenericRuleEvaluator.java:1236)
	at TRANSFORMER/[email protected]/mcjty.incontrol.rules.SpawnRule.match(SpawnRule.java:427)
	at TRANSFORMER/[email protected]/mcjty.incontrol.ForgeEventHandlers.onEntityJoinWorld(ForgeEventHandlers.java:83)
	at TRANSFORMER/[email protected]/mcjty.incontrol.__ForgeEventHandlers_onEntityJoinWorld_EntityJoinLevelEvent.invoke(.dynamic)

[Veynam]

Just here to pitch in, having the EXACT same problem with latest versions of ModernFix as everyone else here

[gabepikamole]

same kind of issue :(

[n24486838]

crash-2024-11-18_02.57.12-server.txt
Minecraft : 1.20.1 (forge 47.3.0)

Hello, I also encountered a very similar problem.
Recently, when I was playing a server with my friends, it would crash when loading into a certain section.

Looking at the crash report it seems to be a problem with ModernFix, can you help me figure out what went wrong?
(The above content is translated using Google, please forgive me for any semantic errors)

Thanks !

[johalun]

I'm also getting this frequently when using /locate or chunky.

[MrBOOMberMAN]

exact same problem here pls fix this

[Kimercal]

same issue
crash-2024-12-03_21.43.17-server.txt

[Cazadorsniper]

I began to have this issue as well, but solved it after removing an Incontrol rule that I had.

[ZenoGrave]

New to making modpacks and stuff. I'm thinking I might have the same or similar issue to these. Not the first time for me on my server that it's done this. I feel like my root might be some of the mods that add alot of entities, but honestly trying to learn as much as I can...
edit: the first time was issues with Nyf's Spiders mod and was resolved after removing it
crash-2024-12-15_23.12.09-server.txt

[johalun]

For me this was the symptom of a problematic structure, causing MC to hang during chunk generation. Without ModernFix MC would still hang, but just no watchdog to report it.

[baronpalmer]

The mod "Nyf's Spiders" has been causing this to happen to me, if you have it installed try removing it