From d967e6754af3cbcdffa1e42c408f5fa93e340293 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Sat, 20 Feb 2016 14:19:34 -0800
Subject: [PATCH 7/9] UPSTREAM: Revert "usb: hub: do not clear BOS field during
 reset device"

This reverts commit d8f00cd685f5c8e0def8593e520a7fef12c22407.

Tony writes:

This upstream commit is causing an oops:
d8f00cd685f5 ("usb: hub: do not clear BOS field during reset device")

This patch has already been included in several -stable kernels.  Here
are the affected kernels:
4.5.0-rc4 (current git)
4.4.2
4.3.6 (currently in review)
4.1.18
3.18.27
3.14.61

How to reproduce the problem:
Boot kernel with slub debugging enabled (otherwise memory corruption
will cause random oopses later instead of immediately)
Plug in USB 3.0 disk to xhci USB 3.0 port
dd if=/dev/sdc of=/dev/null bs=65536
(where /dev/sdc is the USB 3.0 disk)
Unplug USB cable while dd is still going
Oops is immediate:

Reported-by: Tony Battersby <tonyb@cybernetics.com>
Cc: Du, Changbin <changbin.du@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/core/hub.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1560f3f..ac3a7c5 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -5486,8 +5486,11 @@ done:
 	return 0;
 
 re_enumerate:
-	usb_release_bos_descriptor(udev);
-	udev->bos = bos;
+	/* release the new BOS descriptor allocated  by hub_port_init() */
+	if (udev->bos != bos) {
+		usb_release_bos_descriptor(udev);
+		udev->bos = bos;
+	}
 re_enumerate_no_bos:
 	/* LPM state doesn't matter when we're about to destroy the device. */
 	hub_port_logical_disconnect(parent_hub, port1);
-- 
2.8.0.rc3.226.g39d4020