Confirming as of february 11th, this bug has rendered both firefox and thunderbird completely unusable under kubuntu 13. I re-downloaded the newest firefox 27 and still no luck.
:~$ firefox
(process:5934): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed :~$ thunderbird
(process:6095): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
Confirming as of february 11th, this bug has rendered both firefox and thunderbird completely unusable under kubuntu 13. I re-downloaded the newest firefox 27 and still no luck.
:~$ firefox
(process:5934): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
:~$ thunderbird
(process:6095): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed