[PATCH 3.10 43/54] xhci: Fix list corruption in urb dequeue at host removal

Greg Kroah-Hartman
2016-02-24T03:58:01Z

From: Mathias Nyman <mathias.nyman@linux.intel.com>

commit 5c82171167adb8e4ac77b91a42cd49fb211a81a0 upstream.

xhci driver frees data for all devices, both usb2 and and usb3 the
first time usb_remove_hcd() is called, including td_list and and xhci_ring
structures.

When usb_remove_hcd() is called a second time for the second xhci bus it
will try to dequeue all pending urbs, and touches td_list which is already
freed for that endpoint.

Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/host/xhci.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1502,7 +1502,9 @@ int xhci_urb_dequeue(struct usb_hcd *hcd
if (temp == 0xffffffff || (xhci->xhc_state & XHCI_STATE_HALTED)) {
xhci_dbg(xhci, "HW died, freeing TD.\n");
urb_priv = urb->hcpriv;
- for (i = urb_priv->td_cnt; i < urb_priv->length; i++) {
+ for (i = urb_priv->td_cnt;
+ i < urb_priv->length && xhci->devs[urb->dev->slot_id];
+ i++) {
td = urb_priv->td[i];
if (!list_empty(&td->td_list))
list_del_init(&td->td_list);