Corné Dorrestijn

I had the same issue on Linux, also being identified as using a modded client.

---- Minecraft Crash Report ----
// Shall we play a game?

Time: 7/23/14 8:59 PM
Description: Tesselating block model

java.lang.IndexOutOfBoundsException
	at java.nio.Buffer.checkIndex(Buffer.java:532)
	at java.nio.DirectIntBufferU.get(DirectIntBufferU.java:253)
	at chc.a(SourceFile:183)
	at cjs.a(SourceFile:149)
	at cjs.a(SourceFile:81)
	at cjs.a(SourceFile:43)
	at cjs.a(SourceFile:35)
	at cjq.a(SourceFile:62)
	at cmt.b(SourceFile:156)
	at cmm.a(SourceFile:71)
	at cmm.run(SourceFile:31)
	at java.lang.Thread.run(Thread.java:745)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at java.nio.Buffer.checkIndex(Buffer.java:532)
	at java.nio.DirectIntBufferU.get(DirectIntBufferU.java:253)
	at chc.a(SourceFile:183)
	at cjs.a(SourceFile:149)
	at cjs.a(SourceFile:81)

-- Block model being tesselated --
Details:
	Block: minecraft:leaves[check_decay=false,decayable=true,variant=oak]
	Block location: World: (-117,76,-46), Chunk: (at 11,4,2 in -8,-3; contains blocks -128,0,-48 to -113,255,-33), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Using AO: true
Stacktrace:
	at cjs.a(SourceFile:43)
	at cjs.a(SourceFile:35)

-- Block being tesselated --
Details:
	Block type: ID #18 (tile.leaves // axj)
	Block data value: 0 / 0x0 / 0b0000
	Block location: World: (-117,76,-46), Chunk: (at 11,4,2 in -8,-3; contains blocks -128,0,-48 to -113,255,-33), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
Stacktrace:
	at cjq.a(SourceFile:62)
	at cmt.b(SourceFile:156)
	at cmm.a(SourceFile:71)
	at cmm.run(SourceFile:31)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 14w30b
	Operating System: Linux (amd64) version 3.14-1-amd64
	Java Version: 1.7.0_60, Oracle Corporation
	Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 309486232 bytes (295 MB) / 941621248 bytes (898 MB) up to 954728448 bytes (910 MB)
	JVM Flags: 1 total; -Xmx1G
	IntCache: cache: 7, tcache: 75, allocated: 12, tallocated: 94