Patch "xhci: Fix list corruption in urb dequeue at host removal" has been added to the 4.4-stable tree

Patch "xhci: Fix list corruption in urb dequeue at host removal" has been added to the 4.4-stable tree

[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 the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xhci-fix-list-corruption-in-urb-dequeue-at-host-removal.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>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

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
@@ -1549,7 +1549,9 @@ int xhci_urb_dequeue(struct usb_hcd *hcd
 		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);


Patches currently in stable-queue which might be from mathias.nyman@linux.intel.com are

queue-4.4/xhci-fix-list-corruption-in-urb-dequeue-at-host-removal.patch
queue-4.4/revert-xhci-don-t-finish-a-td-if-we-get-a-short-transfer-event-mid-td.patch