[PATCH 3.14 37/37] Revert "usb: hub: do not clear BOS field during reset device"

From: Greg Kroah-Hartman
Date: Sun Apr 17 2016 - 22:29:07 EST


3.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

commit e5bdfd50d6f76077bf8441d130c606229e100d40 upstream.

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@xxxxxxxxxxxxxxx>
Cc: Du, Changbin <changbin.du@xxxxxxxxx>
Cc: Roger Quadros <rogerq@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/usb/core/hub.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -5231,6 +5231,7 @@ static int usb_reset_and_verify_device(s
usb_set_usb2_hardware_lpm(udev, 0);

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

/* Disable LPM and LTM while we reset the device and reinstall the alt
* settings. Device-initiated LPM settings, and system exit latency
@@ -5339,11 +5340,8 @@ 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;

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