As already mentioned, xhci_hcd is to blame. In my configuration I use two sticks: one old MediaTV Pro and one MediaTV Pro III, connected to an ASRock Vision HT (HM87 chipset, i7-4702MQ) also with Ubuntu 14.04 and Tvheadend, getting the same Kernel Ooops constantly.
The setup worked fine on my old computer with Ubuntu 13.10 and kernel 3.11.0.19, albeit with USB 3.0 controllers from Renesas and Fresco Logic, not Intel.
I have not tried to use the aforementioned 3.11 kernel on 14.04 since I hoped for a fix in 3.15 ("xhci: delete endpoints from bandwidth list before freeing whole device"), but this one only seems to defeat an oops in resume from S4/hibernate. Consequently, installing 3.15-utopic from kernel.ubuntu.com didn't change anything.
May be worth knowing that the (one) dedicated USB 2.0 port of the new ASRock leads to the same result and that xhci-crashes are also triggered by a Seagate Backup Plus Slim with Initio INIC-3609 bridge whereas ASMedia and Fujitsu bridges (all USB 3.0) run fine.
Temporarily the sticks are now connected and net-mounted to my old Seagate Dockstar. It's not as snappy as a direct connection and prone to errors if the network is saturated so I really hope for a solid Linux USB 3.0 implementation soon.