[added to the 3.18 stable tree] Revert "usb: hub: do not clear BOS field during reset device"

Sasha Levin
2016-05-19T04:16:03Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit f9b3d78ac42bda9cd30e4c6d0149dba7067c402c.

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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
drivers/usb/core/hub.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d8e1d5c..74d856c 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -5369,6 +5369,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
}

bos = udev->bos;
+ udev->bos = NULL;

for (i = 0; i < SET_CONFIG_TRIES; ++i) {

@@ -5461,11 +5462,8 @@ done:
usb_set_usb2_hardware_lpm(udev, 1);
usb_unlocked_enable_lpm(udev);
usb_enable_ltm(udev);
- /* release the new BOS descriptor allocated by hub_port_init() */
- if (udev->bos != bos) {
- usb_release_bos_descriptor(udev);
- udev->bos = bos;
- }
+ usb_release_bos_descriptor(udev);
+ udev->bos = bos;
return 0;

re_enumerate:
--
2.5.0