Created attachment 106835 [details]
I got this random crash using udisks2 2.1.3-3 on Debian jessie. No idea what I was doing at the time though. gdb trace attached.
Maybe this is relevant to the issue: https://bugzilla.gnome.org/show_bug.cgi?id=707298. Apparently, there has been a bug in glib-2.40 which is fixed in glib-2.40.1. Does the following work for you:
The crash was random, no idea what triggered it so it isn't possible to reproduce it. Debian jessie has now moved on to glib 2.42.0-2 so the issue you mentioned is no longer relevant. Checking my mail archives and logs, the last new udisks crash was 2014-09-26 and I upgraded from glib 2.40.0-5 to 2.42.0-1 on 2014-09-29. So I think it is plausible that this is fixed already. If you agree or don't think the backtrace is useful, feel free to close the bug.
This crashed deep in glib's own signal/thread handling, there's no udisks code in the stack trace. So indeed, let's blame that glib fix as you didn't get further crashes since then. Thanks for checking!