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>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 350dcd9af5d86eb2181e6cc8f77f25a33f712cce..51b436918f7892b1249c7ec1b19dad515a9a5755 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -5401,6 +5401,7 @@ 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) {
 
@@ -5493,11 +5494,8 @@ 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: