Server appears to hang but can send data to players

imjack commented 5 years ago

Expected Behavior

The server should run without randomly hanging/stalling.

Actual Behavior

The server will randomly stop accepting new player connections, and the player will feel a "lag" effect and their messages will be delayed 30+ seconds but the client will not disconnect. If the server console uses /tell or /say the player will get the packet fine. Plugins such as pocketvote can continue to poll the API.

Steps to Reproduce

We can't find the cause but will happen randomly but usually will happen with 50+ players online.

We feel this might be an exploit, so in addition to a person finding the cause or releasing the exploit I will be happy to put a bug bounty of £50 to reward the person or a chosen charity

Debug information

Debug link: debugpaste=> 19:21:00 [INFO ] ---- Server status ---- 19:21:00 [INFO ] Uptime: 1 days 0 hours 6 minutes 5 seconds 19:21:00 [INFO ] Current TPS: 20.0 19:21:00 [INFO ] Load: 10.71% 19:21:00 [INFO ] Network upload: 0.0 kB/s 19:21:00 [INFO ] Network download: 0.0 kB/s 19:21:00 [INFO ] Thread count: 33 19:21:00 [INFO ] Used memory: 311.19 MB. (4.27%) 19:21:00 [INFO ] Total memory: 480.5 MB. 19:21:00 [INFO ] Maximum VM memory: 7282.0 MB. 19:21:00 [INFO ] Available processors: 8 19:21:00 [INFO ] Players: 28 online, 125 max. 19:21:00 [INFO ] World "world": 372 chunks, 5 entities, 397 blockEntities. Time 1.0ms 19:21:00 [INFO ] World "nether": 0 chunks, 0 entities, 0 blockEntities. Time 0.0ms 19:21:00 [INFO ] World "skyblock": 5187 chunks, 60 entities, 3180 blockEntities. Time 4.0ms 19:21:00 [INFO ] World "kitpvp": 7 chunks, 0 entities, 8 blockEntities. Time 0.0ms

Checklist:

[x] I included a /debugpaste link
[x] I made sure there aren't duplicates of this report (Use Search)
[x] I made sure I am using an up-to-date version of Nukkit
[x] I Made sure the bug/error is not caused by a plugin

Creeperface01 commented 5 years ago

Maybe try to get some thread dump?

imjack commented 5 years ago

Here is a dump during the issue https://gist.github.com/imjack/e21a1f82d512ff7088dde44b7f4b247d

hteppl commented 5 years ago

Same problem!

imjack commented 5 years ago

Same problem!

How many players are online during the error?

hteppl commented 5 years ago

I can't find the cause too. This bug comes with 10-15 players online.

Creeperface01 commented 5 years ago

What plugins do you use?

hteppl commented 5 years ago

What plugins do you use?

MobPlugin, DbLib and my plugin for anarchy which use sql connection.

hteppl commented 5 years ago

Mmm

imjack commented 5 years ago

Appears to be fixed on the new raknet branch. Thanks to @SupremeMortal

CloudburstMC / Nukkit