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[3.13.y-ckt,040/138] xhci: Fix list corruption in urb dequeue at host removal

Message ID 1457565265-15195-41-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa March 9, 2016, 11:12 p.m. UTC 
3.13.11-ckt36 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/usb/host/xhci.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index c363a36..3bd7470 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1527,7 +1527,9 @@  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);