[PATCH 4.4 039/113] USB: hub: change the locking in hub_activate

Greg Kroah-Hartman
2016-09-05T16:51:13Z

From: Alan Stern <stern@rowland.harvard.edu>

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@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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
@@ -1036,7 +1036,7 @@ 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)
@@ -1243,7 +1243,7 @@ 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);
@@ -1266,7 +1266,7 @@ 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);