So I've got a hung emacs that I have attached to in a debugger.  I opened a
new emacs to use report-emacs-bug; following the instructions I was going
to include the output of 'bt full'.  Except that it's about 17500 lines
long...

I took a look at the backtrace as well, and of the 3800 calls on the list,
~3700 of them are from either mark_object or mark_vectorlike.

I'm not sure what else to do (I'm not familiar with emacs c code at all),
but I can keep the hung emacs running in the debugger pretty much
indefinitely if that's useful.

I submitted a report to debbugs with the interesting portions of the
backtrace output.

-- 
Geoff

Nothing is ever easy.