After being in the nether for a while (~2 hours or so), the game will start regularly crashing whenever I am in the Nether. The crashes can happen anywhere between 30 seconds after logging in to an hour after logging in. The crashes only occur in the nether- the game runs fine in the overworld.

This has happened on 2 different worlds. The problem occurs both with no extra java arguments and with arguments increasing the max memory to 1GB or 2GB. It happens both with the lwjgl libraries included with Minecraft and the fixed up-to-date libraries.

The crash results in any one of these 3 errors:
Bus Error
Trace/Breakpoint Trap
SIGSEGV (Segmentation Fault)

None of these errors generates a crash report in the .minecraft folder, but the 3rd error (the segmentation fault) generates a log. I have attached one of these logs: