From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> commit 1245374e9b8340fc255fd51b2015173a83050d03 upstream. At xhci removal the USB3 hcd (shared_hcd) is removed before the primary USB2 hcd. Interrupts for port status changes may still occur for USB3 ports after the shared_hcd is freed, causing NULL pointer dereference. Check if xhci->shared_hcd is still valid before handing USB3 port events Cc: <stable@xxxxxxxxxxxxxxx> Reported-by: Peter Chen <peter.chen@xxxxxxx> Tested-by: Jack Pham <jackp@xxxxxxxxxxxxxx> Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Cc: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx> [redone for 4.14.y based on Mathias's comments] Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/host/xhci-ring.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1640,6 +1640,12 @@ static void handle_port_status(struct xh if ((major_revision == 0x03) != (hcd->speed >= HCD_USB3)) hcd = xhci->shared_hcd; + if (!hcd) { + xhci_dbg(xhci, "No hcd found for port %u event\n", port_id); + bogus_port_status = true; + goto cleanup; + } + if (major_revision == 0) { xhci_warn(xhci, "Event for port %u not in " "Extended Capabilities, ignoring.\n",