Crash when server restart

[GamakCZ]

Issue description

pthreads detected an attempt to connect to an object which has already been destroyed

Steps to reproduce the issue

reload, restart, start

OS and versions

• Genisys: 0000000000000000000000000000000000000000 [Protocol 82; API 2.0.0]
• PHP: 7.0.2
• Server OS: Linux
• Game version: 0.15.7

  Crashdump, backtrace, memory dumps, plugins list or other files

Genisys Crash Dump Sat Sep 10 20:01:03 CEST 2016

Error: pthreads detected an attempt to connect to an object which has already been destroyed
File: /src/pocketmine/scheduler/AsyncTask
Line: 85
Type: notice

Code:
[76]
[77] public function isCrashed(){
[78] return $this->crashed;
[79] }
[80]
[81] /**
[82] * @return mixed
[83] */
[84] public function getResult(){
[85] return $this->serialized ? unserialize($this->result) : $this->result;
[86] }
[87]
[88] public function cancelRun(){
[89] $this->cancelRun = true;
[90] }
[91]
[92] public function hasCancelledRun(){
[93] return $this->cancelRun === true;
[94] }
[95]

Backtrace:
#0 /LS.phar/src/aliuly/livesigns/FetchTask(80): pocketmine\scheduler\AsyncTask->getResult(boolean)
#1 /src/pocketmine/scheduler/AsyncPool(151): aliuly\livesigns\FetchTask->onCompletion(pocketmine\Server object)
#2 /src/pocketmine/scheduler/ServerScheduler(268): pocketmine\scheduler\AsyncPool->collectTasks(boolean)
#3 /src/pocketmine/Server(2873): pocketmine\scheduler\ServerScheduler->mainThreadHeartbeat(integer 8)
#4 /src/pocketmine/Server(2571): pocketmine\Server->tick(boolean)
#5 /src/pocketmine/Server(2449): pocketmine\Server->tickProcessor(boolean)
#6 /src/pocketmine/Server(2035): pocketmine\Server->start(boolean)
#7 /src/pocketmine/PocketMine(467): pocketmine\Server->__construct(pocketmine\CompatibleClassLoader object, pocketmine\utils\MainLogger object, string phar:///hlserver/27097/PocketMine-MP.phar/, string /hlserver/27097/, string /hlserver/27097/plugins/, string unknown)
#8 (1): require_once(string phar:///hlserver/27097/PocketMine-MP.phar/src/pocketmine/PocketMine.php)

Genisys version: 0000000000000000000000000000000000000000 [Protocol 82; API 2.0.0]
uname -a: Linux casa24 4.1.0 #2 SMP Sun Jun 28 20:57:39 CEST 2015 x86_64
PHP version: 7.0.2
Zend version: 3.0.0
OS : Linux, linux

Server uptime: 1 seconds
Number of loaded worlds: 6
Players online: 0/25

Loaded plugins:
MagicInfo 1 by SwagCraftTeam for API(s) 1.0.0, 1.3.0, 1.8.0
WCore 1 by GamakCZ for API(s) 2.0.0.
ServerAuth 2.13 by EvolSoft for API(s) 1.11.0
AfkKick 1.1 by XxDXM_hippiexX for API(s) 1.11.0, 1.13.0
PurePerms 1.3.6 by 64FF00 for API(s) 1.13.0, 2.0.0
LiveSigns 1.2.1 by aliuly for API(s) 1.12.0, 2.0.0
WorldEditPE 1 by GamaK for API(s) 2.0.0
Broadcaster 1.16 by EvolSoft for API(s) 1.12.0
TapToDo 2.2.1 by Falk for API(s) 1.0.0
BanItem 2.1 by LDX for API(s) 1.0.0
ManyWorlds 2.0.3 by aliuly for API(s) 2.0.0
SmashDoDo 2.0.0 ENG by KaitoDoDo for API(s) 1.0.0, 2.0.0
BedWars 1.3.1 by Bluplayz, GamakCZ for API(s) 1.13.0, 1.8.0, 2.0.0
PvPWorlds 1 by for API(s) 1.0.0
ColorMatch 1.1.2 by CreeperFace for API(s) 1.12.0
SkyBlock 1.5.6 by for API(s) 1.12.0
ChatLogin 1.4 by EvolSoft for API(s) 1.11.0
iProtector 3.1b by LDX for API(s) 1.9.0, 2.0.0
MicroBattles 2.3.0 by KaitoDoDo+LittleBigMC for API(s) 1.0.0, 2.0.0
PocketGuard 2.1.1 by MinecrafterJPN for API(s) 1.10.0
SW_svile 0.6dev by svile for API(s) 1.13.0
Alias 1.2.0 by ZacHack for API(s) 1.12.0
AntiSpam 1.2 by xBeastMode for API(s) 1.13.1
VoteReward 3 by LDX for API(s) 1.12.0, 2.0.0
ServerKits 1.3 by EvolSoft for API(s) 1.11.0
Slapper 1.2.9.7 by jojoe77777 for API(s) 2.0.0
CustomAlerts 1.6_PHP7 by EvolSoft for API(s) 1.3.0, 1.8.0, 2.0.0
1vs1 0.0.5 by for API(s) 1.0.0, 1.1.0
PocketMoney 4.0.1 by MinecrafterJPN, MinecrafterJPN for API(s) 1.10.0
Essentials 1 by LegendsOfMCPE Team for API(s) 1.13.0, 2.0.0
ChestShop 2.0.1 by MinecrafterJPN, MinecrafterJPN for API(s) 1.10.0
MyPlot 1 by Wies and Exxarion for API(s) 1.0.0
PureChat 1.4.0 by 64FF00 for API(s) 1.13.0, 2.0.0

[Muqsit]

Plugin fault. Remove LiveSigns 1.2.1 by aliuly for API(s) 1.12.0, 2.0.0