As previously noted, mainline commit 27a41a83ec54 ("xhci: Cleanup only when releasing primary hcd") causes this boot hang. I can reproduce the problem with VirtualBox 5.1.x, booting any kernel version which includes that commit (Xenial, Yakkety, or mainline v4.7-rc1).
I think I have identified the specific problem in that commit and have a constructed a test patch (attached for reference). This appears to fix the VirtualBox boot hang but I'd like some confirmation that it results in otherwise normal USB3.0 functionality. Here's a Xenial test kernel with the test patch applied: http://people.canonical.com/~kamal/lp1604058/ Affected users, please advise whether this fixes the boot hang in your VirtualBox environment, and whether your USB3.0 behavior is back to normal. ** Patch added: "0001-TEST-xhci-Fix-soft-lockup-in-xhci_pci_probe-path-whe.patch" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1604058/+attachment/4705504/+files/0001-TEST-xhci-Fix-soft-lockup-in-xhci_pci_probe-path-whe.patch ** Changed in: linux (Ubuntu Xenial) Assignee: Joseph Salisbury (jsalisbury) => Kamal Mostafa (kamalmostafa) ** Changed in: linux (Ubuntu) Assignee: Joseph Salisbury (jsalisbury) => Kamal Mostafa (kamalmostafa) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1604058 Title: virtualbox+usb 3.0 breaks boot, -28 kernel works To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1604058/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs