I can confirm this bug. Its easy to reproduce it. Since I'm having two X servers (ie. :0 and :1) on the physical PC/display) running, sometimes (ie. not always), I see the following error produced on the X server screen that didn't crash:
*** glibc detected *** free(): invalid pointer 0x082d1508 or at a different address: 0x08446680. Possibly this address isn't constant across crashes. Xorg.0.log attached. ** Attachment added: "Bug confirmed and reproducable" http://librarian.launchpad.net/4631539/Xorg.0.log.old -- Update Manager crashes xorg https://launchpad.net/bugs/50054 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs