Patch "USB: hub: change the locking in hub_activate" has been added to the 4.4-stable tree

Patch "USB: hub: change the locking in hub_activate" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    USB: hub: change the locking in hub_activate

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-hub-change-the-locking-in-hub_activate.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 07d316a22e119fa301fd7dba7f1e1adfd4f72c05 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@rowland.harvard.edu>
Date: Fri, 5 Aug 2016 11:51:30 -0400
Subject: USB: hub: change the locking in hub_activate

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);


Patches currently in stable-queue which might be from stern@rowland.harvard.edu are

queue-4.4/usb-ehci-change-order-of-register-cleanup-during-shutdown.patch
queue-4.4/usb-hub-fix-up-early-exit-pathway-in-hub_activate.patch
queue-4.4/usb-hub-change-the-locking-in-hub_activate.patch
queue-4.4/usb-validate-wmaxpacketvalue-entries-in-endpoint-descriptors.patch
queue-4.4/usb-serial-fix-memleak-in-driver-registration-error-path.patch
queue-4.4/usb-hub-fix-unbalanced-reference-count-memory-leak-deadlocks.patch
queue-4.4/usb-misc-usbtest-add-fix-for-driver-hang.patch