Hi Levente,

I directed stdout to a file and prior to the freeze, did:

pkill -USR1 -n -x squeak

a few times and noticed "stack overflow" mentioned twice. After the freeze, 
pkill sent nothing else to stdout. Maybe something in stderr? I'll try 
again and concatenate stderr to the end of stdout. Meanwhile, the file with 
the stack overflows is attached.

Thanks for the help.

 - Dan

On Sat, 28 Jan 2017, Levente Uzonyi wrote:

>Hi Dan,

>You can send the USR1 signal to the VM process to make it write some debug 
>information to the console. With this information you can easily tell 
>what's happening. I suspect it's stuck in a long GC.


>On Fri, 27 Jan 2017, Dan Norton wrote:

>> On Debian8, CogSpur64 5.0-201612221637, Cuis 5.0 3043...
>> after lots of user interaction, views opening and closing, and 
>> animation, the image becomes unresponsive. Cmd+. does nothing and the 
>> clock in the Cuis taskbar no longer updates. The length of time to 
>> produce this varies from 5 to 20 minutes.
>> There seems to be no dump and no log. 'Smalltalk garbageCollectMost' 
>> reports 25550736 to 30517872 over 34 samples.
>> Sorry to be so vague. This has occurred with several images - sometimes 
>> scrolling through a senders list, or stepping through a debugger, but 
>> repeatably with one of my images. I can supply this image, warmed up so 
>> that it might not take so long to reproduce the problem if you would 
>> like. Or give me a hint as to how to narrow down the problem