[SPIGOT-4761] [VANILLA] ConcurrentModificationException while ticking world Created: 25/Apr/19  Updated: 13/May/19  Resolved: 13/May/19

Status: Resolved
Project: Spigot
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Bug Priority: Minor
Reporter: Chase Assignee: Unassigned
Resolution: Fixed Votes: 3
Labels: 1.14, crash, vanilla
Environment:

Linux AMD 8 core CPU

10gb of ram

 

Windows 10 60bit

8gb of ram

AMD Ryzen 2700x

Attachments: Text File crash-2019-04-26_00.13.14-server.txt    
Issue Links:
Duplicate
is duplicated by SPIGOT-4839 ConcurrentModificationException net.m... Resolved
is duplicated by SPIGOT-4786 Server crashed with ConcurrentModific... Resolved
is duplicated by SPIGOT-4846 server crash - b2248 - Encountered an... Resolved
Version: CraftBukkit version git-Spigot-0c02b0c-e879c44 (MC: 1.14) (Implementing API version 1.14-R0.1-SNAPSHOT)
Plugin: https://www.spigotmc.org/resources/worldborder.60905/
Guidelines Read: Yes

 Description   

https://bugs.mojang.com/browse/MC-148830

The specific crash seems to have been reported in many scenarios, however, the only way I can encounter it is by using WorldBoarder and attempting to pre-gen a world at 200 frequency,

 

Install Latest world border and run commands below supplementing <world> with a pre-existing world.

Setting a 20k by 20k radius using 

 /wb <world> set 10000 10000 0 0

And starting the fill using 

/wb <world> fill 200 208

 

Wait and server should crash and spawn a crash log

 

The bug was reported to Mojang in pre5 and it still exists so I don't see a patch coming anytime soon.

 Comments   
Comment by md_5 [ 13/May/19 ]

Resolved in upcoming 1.14.1 version

Comment by Johnibur [ 10/May/19 ]

This issue is fixed in vanilla 1.14.1-pre1.

Comment by minecraft7net [ 02/May/19 ]

any workaround for this ?

Comment by Luis Castellano [ 30/Apr/19 ]

This happens eventually to me too, when exploring the world

Comment by sam newman [ 29/Apr/19 ]

I was about to make a report for the same thing. I've noticed auto-saves hang the server hard and also doesn't save properly sometimes when stopping the server, it just hangs. This issue making my server crash has made 1.14 unuseable.

Comment by md_5 [ 28/Apr/19 ]

Ross - given the issue will almost certainly be fixed in 1.14.1, I would rather not make a change I am not fully aware of the consequences for.

 

>for spigot servers due to auto-save behavior delaying region file writes.

 

That would be a bug, I see you have opened a report at least for API driven saves

 

Comment by Ross [ 27/Apr/19 ]

@md_5 would it be possible to trap the exception and recover, or at least shutdown gracefully so playerdata gets saved and as many regions as possible? Or should we all just wait for 1.14.1? This bug looks like it makes 1.14 non-viable for spigot servers due to auto-save behavior delaying region file writes. At least a pure vanilla server jar would have a better recovery chance (or at least less data loss) from this constant crashing.

Comment by md_5 [ 26/Apr/19 ]

Yeah, I've left some comments on the Mojang issue.

Not sure of a fix - the related code is very complicated.

Comment by Chase [ 26/Apr/19 ]

Occurred within seconds (check timestamp)

https://hastebin.com/acimilahun.md

Comment by Chase [ 26/Apr/19 ]

The rate of it occurring for me is within seconds of a server startup when world border starts to automatically fill again. I can't pre-generate the world for more than a few minutes and even seconds in some cases. If you can't reproduce constantly do a 

/wb fill cancel

and restart it, usually, that triggers it.

Comment by md_5 [ 25/Apr/19 ]

Hmm I reproduced it once, but no more

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