patch "xhci: Fix list corruption in urb dequeue at host removal" added to usb-linus

patch "xhci: Fix list corruption in urb dequeue at host removal" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    xhci: Fix list corruption in urb dequeue at host removal

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 5c82171167adb8e4ac77b91a42cd49fb211a81a0 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Tue, 26 Jan 2016 17:50:12 +0200
Subject: xhci: Fix list corruption in urb dequeue at host removal

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.

Cc: <stable@vger.kernel.org>
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(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 26a44c0e969e..0c8087d3c313 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1554,7 +1554,9 @@ 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);
-- 
2.7.0