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Commit c193fcec authored by Mathias Nyman's avatar Mathias Nyman Committed by Greg Kroah-Hartman
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usb: hub: Fix locking issues with address0_mutex 



commit 6cca13de26eea6d32a98d96d916a048d16a12822 upstream.

Fix the circular lock dependency and unbalanced unlock of addess0_mutex
introduced when fixing an address0_mutex enumeration retry race in commit
ae6dc22d2d1 ("usb: hub: Fix usb enumeration issue due to address0 race")

Make sure locking order between port_dev->status_lock and address0_mutex
is correct, and that address0_mutex is not unlocked in hub_port_connect
"done:" codepath which may be reached without locking address0_mutex

Fixes: 6ae6dc22d2d1 ("usb: hub: Fix usb enumeration issue due to address0 race")
Cc: <stable@vger.kernel.org>
Reported-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Tested-by: default avatarHans de Goede <hdegoede@redhat.com>
Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211123101656.1113518-1-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b13daa1c

drivers/usb/core/hub.c

+12 −7
Original line number Diff line number Diff line
@@ -4835,6 +4835,7 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, 
	struct usb_port *port_dev = hub->ports[port1 - 1];

	struct usb_device *udev = port_dev->child;

	static int unreliable_port = -1;

	bool retry_locked;



	/* Disconnect any existing devices under this port */

	if (udev) {
@@ -4891,9 +4892,10 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, 


	status = 0;



	mutex_lock(hcd->address0_mutex);



	for (i = 0; i < SET_CONFIG_TRIES; i++) {

		usb_lock_port(port_dev);

		mutex_lock(hcd->address0_mutex);

		retry_locked = true;



		/* reallocate for each attempt, since references

		 * to the previous one can escape in various ways
@@ -4902,6 +4904,8 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, 
		if (!udev) {

			dev_err(&port_dev->dev,

					"couldn't allocate usb_device\n");

			mutex_unlock(hcd->address0_mutex);

			usb_unlock_port(port_dev);

			goto done;

		}
@@ -4923,13 +4927,13 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, 
		}



		/* reset (non-USB 3.0 devices) and get descriptor */

		usb_lock_port(port_dev);

		status = hub_port_init(hub, udev, port1, i);

		usb_unlock_port(port_dev);

		if (status < 0)

			goto loop;



		mutex_unlock(hcd->address0_mutex);

		usb_unlock_port(port_dev);

		retry_locked = false;



		if (udev->quirks & USB_QUIRK_DELAY_INIT)

			msleep(2000);
@@ -5019,11 +5023,14 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, 


loop_disable:

		hub_port_disable(hub, port1, 1);

		mutex_lock(hcd->address0_mutex);

loop:

		usb_ep0_reinit(udev);

		release_devnum(udev);

		hub_free_dev(udev);

		if (retry_locked) {

			mutex_unlock(hcd->address0_mutex);

			usb_unlock_port(port_dev);

		}

		usb_put_dev(udev);

		if ((status == -ENOTCONN) || (status == -ENOTSUPP))

			break;
@@ -5046,8 +5053,6 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, 
	}



done:

	mutex_unlock(hcd->address0_mutex);



	hub_port_disable(hub, port1, 1);

	if (hcd->driver->relinquish_port && !hub->hdev->parent) {

		if (status != -ENOTCONN && status != -ENODEV)