[Qt-interest] SIGSEGV with single-line gdb backtrace

[Josiah Bryan]

Hey All -

I'm working on a project that uses ffmpeg to decode video that plays in 
a QGraphicsItem in a QGraphicsView. The scene/items are reused in a 
custom QAbstractListView to paint thumnail snaphots of the scene as its 
being edited.

Well, as the program is loading, it goes through the process of building 
the snapshots - then all of a sudden, throws a SIGSEGV. Being a good 
little programmer, I run it inside gdb, and when it dies, I ask gdb for 
a backtrace (bt). Much to my suprise, it gives a single line backtrace. 
Right before the SIGSEGV, I get a bunch of QThread destroyed errors:

QThread: Destroyed while thread is still running
QThread: Destroyed while thread is still running

Then the sigsegv:

Program received signal SIGSEGV, Segmentation fault.
0x0063ca47 in ?? ()
(gdb) bt
#0  0x0063ca47 in ?? ()

Any ideas on how to figure this one out? I mean, this could be in any 
number of areas of the code - how can I isolate the crash with no stack 
trace?

Thanks!
-josiah