STEPS TO REPRODUCE (warning the URL is a fuzz tester that creates (a few) new windows) 1. load URL, wait ACTUAL RESULT see attached debug data - it appears the local SVGMatrix 'm' was filled with NaN values for some reason: http://hg.mozilla.org/mozilla-central/annotate/c1ee454506f6/layout/svg/nsSVGGlyphFrame.cpp#l1812

Do you need to close any dialogs that appear, in order to trigger this? (In my linux debug build, I get a few modal "this search engine isn't supported by nightly and can't be installed" popups, and a file-picker dialog asking me to open a file.) Also, how long did you need to wait before the assertion-failures in your attached log?

> Do you need to close any dialogs that appear Don't remember, sorry. > I get a few modal "this search engine isn't supported" There's a workaround for that in bug 839736 comment 1. > Also, how long did you need to wait An hour or so, iirc.

nsSVGGlyphFrame is no more.