I'm running PICO-8 in Ubuntu 14.04 on a Toshiba Chromebook 2 through crouton and after about 15-20 minutes it crashes my Chromebook. Before I updated crouton two days ago it would only take about 30 seconds before it crashes. Any ideas on how to fix this or somehow generate a log of what's happening when this happens?

Could you try generating a stack trace with gdb from commandline?

gdb pico8
run

Does it know roughly what was happening when it crashes? (e.g. in the editor, or playing a cartridge)

I'll run a stack trace in a bit. It has crashed in the editor, playing a cartridge, and just sitting on the start screen.

If it crashes on the start screen, my first suspicion would be the audio mixer (which still operates even during silence). It really isn't doing much else except blitting to screen with time-tested code -- not that I completely trust anything. I'll put an option to turn off the mixer in 0.1.2 as a stab in the dark if the crash log doesn't give any clues.

Here's the output of gdb. It crashed right after opening it.

Starting program: /home/kurtosterhage/Downloads/PICO-8/pico-8/pico8 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff70e4700 (LWP 28722)]
Traceback (most recent call last):
  File "/usr/share/gdb/auto-load/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.19-gdb.py", line 63, in <module>
    from libstdcxx.v6.printers import register_libstdcxx_printers
ImportError: No module named 'libstdcxx'
[New Thread 0x7fffeb204700 (LWP 28723)]
[Thread 0x7fffeb204700 (LWP 28723) exited]
[New Thread 0x7fffeb204700 (LWP 28726)]

Program received signal SIGCONT, Continued.
[Switching to Thread 0x7ffff70e4700 (LWP 28722)]
sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:85
85  ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S: No such file or directory.

That GDB crash looks like a fairly widespread issue.

I had the same issues. Try running full screen. It doesn't crash for me anymore if I'm in full screen.

Well, I was never able to get a crash log with anything helpful in it. Ran across a guide to natively run Linux on my Toshiba CB2 and put Ubuntu GNOME 15.04 on it. Haven't had a crash with PICO-8 since then. Not sure if it's an issue with how crouton works or possibly an issue with the kernel in 14.04, since that kernel is a little behind these days.