[PATCH 4.7 038/143] USB: hub: change the locking in hub_activate

[Greg Kroah-Hartman]

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

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

From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

commit 07d316a22e119fa301fd7dba7f1e1adfd4f72c05 upstream.

The locking in hub_activate() is not adequate to provide full mutual
exclusion with hub_quiesce().  The subroutine locks the hub's
usb_interface, but the callers of hub_quiesce() (such as
hub_pre_reset() and hub_event()) hold the lock to the hub's
usb_device.

This patch changes hub_activate() to make it acquire the same lock as
those other routines.

Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/core/hub.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1052,7 +1052,7 @@ static void hub_activate(struct usb_hub
 
 	/* Continue a partial initialization */
 	if (type == HUB_INIT2 || type == HUB_INIT3) {
-		device_lock(hub->intfdev);
+		device_lock(&hdev->dev);
 
 		/* Was the hub disconnected while we were waiting? */
 		if (hub->disconnected)
@@ -1259,7 +1259,7 @@ static void hub_activate(struct usb_hub
 			queue_delayed_work(system_power_efficient_wq,
 					&hub->init_work,
 					msecs_to_jiffies(delay));
-			device_unlock(hub->intfdev);
+			device_unlock(&hdev->dev);
 			return;		/* Continues at init3: below */
 		} else {
 			msleep(delay);
@@ -1282,7 +1282,7 @@ static void hub_activate(struct usb_hub
 		/* Allow autosuspend if it was suppressed */
  disconnected:
 		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
-		device_unlock(hub->intfdev);
+		device_unlock(&hdev->dev);
 	}
 
 	kref_put(&hub->kref, hub_release);