I can see the same problem. Downgrading to the -23 kernel works around the problem for me, but with -25 it's reproducible.
** Changed in: xorg (Ubuntu) Status: Unconfirmed => Confirmed -- X crashes when viewing a file with long lines in firefox https://launchpad.net/bugs/51180 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs