Nothing wrong in this dump. There's no deadlock and all threads are in normal wait state.

Probably a freeze caused in your X11 display server by another X11 application: possibly a screensaver not starting properly or wanting to grab your mouse/keyboard input focus?
Does it occur if you disable your X11 screensaver?

Also check the status of your window manager. There may be some uncaught conditions. (Look at its log). Does it occur if you switch to another window manager (Motif, twm, ...)?

Also check the status of your X11 font server. May be there are logs indicating that it fails to initialize some font properly. May be caused by a corrupted font, or a font feature not working properly. This may cause the X11 display server to wait for a reply from the X11 font server. (check the logs too). I've read that the support and integration of TrueType font servers for X11 display servers was still not finished, or that some features in OpenType fonts were particularly slow or consuming too much resource. (Try disabling the TrueType fonts: does it still occur?)