Created attachment 17841 [details] [review]
Found in Inkscape.
When opening the SVG Fonts editing pane, Inkscape freezes as soon as a font name is selected. It turns out that Windows hangs an app on entering a mutex when that mutex has been exited more times than it has been entered, i.e. the sequence goes init, enter, exit, exit, enter:deadlock. Patch attached. The fix is in common code, but I haven't seen any instance of in not being caused by user fonts, nor have I tried to read the code to see if it could be.
NB: This description sounds a lot like bug 11900, but it can't be because the offending code was only written in May.
Author: Behdad Esfahbod <email@example.com>
Date: Mon Sep 15 18:51:24 2008 -0400
[scaled-font] Fix bug unlocking the wrong mutex (#16819)