[PATCH 3.16 06/63] usbip: usbip_host: fix to hold parent lock for device_attach() calls

[Ben Hutchings]

3.16.58-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>

commit 4bfb141bc01312a817d36627cc47c93f801c216d upstream.

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

Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/staging/usbip/stub_main.c | 5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/staging/usbip/stub_main.c
+++ b/drivers/staging/usbip/stub_main.c
@@ -205,7 +205,12 @@ 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;