[PATCH 4.4 05/44] usbip: usbip_host: fix to hold parent lock for device_attach() calls

[Greg Kroah-Hartman]

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

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

From: Shuah Khan <shua...@osg.samsung.com>

commit 4bfb141bc01312a817d36627cc47c93f801c216d upstream.

usbip_host calls device_attach() without holding dev->parent lock.
Fix it.

Signed-off-by: Shuah Khan <shua...@osg.samsung.com>
Cc: stable <sta...@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/usb/usbip/stub_main.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/usb/usbip/stub_main.c
+++ b/drivers/usb/usbip/stub_main.c
@@ -201,7 +201,12 @@ static ssize_t rebind_store(struct devic
        if (!bid)
                return -ENODEV;
 
+       /* device_attach() callers should hold parent lock for USB */
+       if (bid->udev->dev.parent)
+               device_lock(bid->udev->dev.parent);
        ret = device_attach(&bid->udev->dev);
+       if (bid->udev->dev.parent)
+               device_unlock(bid->udev->dev.parent);
        if (ret < 0) {
                dev_err(&bid->udev->dev, "rebind failed\n");
                return ret;