Bukkit

Describe to us the issue that you're having:

Which steps will reproduce this problem?:
1) Server undergoes a bot attack
2) I get errors during the attack seemingly from bpermissions
3) The bot attack ends but fifteen minutes or so, later server stops responding and crashes leading to loss of data.

This has happened twice so far.
....

Do you have an error log of what happened?
Yes, a few instances of the errors that happen during the bot attack are here:
http://pastebin.com/FETq6rQq

The information in the logs after the server crashes are here:
"server thread dump"
http://pastebin.com/4vLc8D9S

please let me know if you need the "entire thread dump".

Which version of bPermissions are you using?: (Please don't say "latest"!!!)
bPermissions version 2.10.9m

Which version of CraftBukkit?: (Please don't say "latest"!!!)
The server is running CraftBukkit version git-Spigot-044d928-e8c6403 (MC: 1.8.6) (Implementing API version 1.8.6-R0.1-SNAPSHOT)

Which OS?
I am hosting the server on beastnode shared host. They use a multicraft panel. I am not sure what OS they use but it is probably some linux variant.

Any other information we may need (plugins, configs, etc):

The server runs in offline mode and I use the authme reloaded plugin which has an anti bot feature. if too many player join the server in too short a time, it goes into anti bot mode and blocks further players from joining for about ten minutes from the start of attack. The server crash occurs many minutes after the anti bot thing deactivates.

I also use the skins changer mod which loads player skins when they join the server.
Apart from that I use essentials, multiverse, towny, mcmmo, plotsquared and some other less important plugins. Let me know if you need a complete list.

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