VM crashes when xHCI controller is reset while USB3 disk is attached

[mgrzegor]

Since VirtualBox version 6.1.36 my Ubuntu VM crashes if I reset the xHCI controller (which I occasionally have to do due to another issue) while one or more of my SuperSpeed (i.e. USB 3.0) external disks are attached to the VM.

The crash also occurs on system boot if one of those disks are attached (which I usually do not do).

Reproduction steps:

1. Start the VM, wait for the GUI to come up.
2. Start gnome-terminal.
3. In the terminal window, type:
   sudo -i
   (to obtain root prompt).
4. Via the VM menu -> Devices -> USB, attach a USB 3.0 disk to the VM.
5. In the terminal window, type:
   echo -n "0000:00:0c.0" > /sys/bus/pci/drivers/xhci_hcd/unbind

Result: VM crashes with an "unhandled exception" message (log attached).

The crash does not occur if a high-speed (USB 2.0) disk is attached, or if no USB devices are attached.

In all previous versions of VirtualBox I have used (back to at least 5.0.40) I observed no such crashes.

A workaround is to:

• not attach USB 3..0 devices while booting the guest
• detach all USB 3.0 devices before resetting the xHCI controller
• pray that no xHCI controller reset occurs while I am using any of my USB 3.0 disks (such resets have been observed to occur sporadically in all previous versions of VirtualBox, and have been harmless before.)

[Sean Wang]

Reproduced in windows 10 guest

[mgrzegor]

Appears to be fixed in 6.1.40 (doing the reproduction steps no longer results in a crash).

[aeichner]

Thanks for the feedback, there was indeed a fix related to this in 6.1.40.