From: Mathias Nyman <[email protected]>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

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 <[email protected]>
Tested-by: Joe Lawrence <[email protected]>
Signed-off-by: Mathias Nyman <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
---
 drivers/usb/host/xhci.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index dfcf0a3527b8..806ed2ba1c6e 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1522,7 +1522,9 @@ int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb 
*urb, int status)
                xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                                "HW died, freeing TD.");
                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);
-- 
2.7.1

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