On Wed, 10 Sep 2014 22:09:08 +0300, Eli Zaretskii wrote:
>
> Please run Emacs under GDB, and when this happens again, produce a
> full backtrace and post it here.  I'd like to see if the symptoms are
> similar to what Ken reported in bug #17817.

It finally happened again; backtrace attached (gzipped because it's 
over 100K uncompressed).