usb: hub: Fix locking issues with address0_mutex

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: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211123101656.1113518-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 00c3506324e47d341dd4c7eb86e77829ca7acdf0..00070a8a65079206648ca39f83f35cdef9038601 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -5188,6 +5188,7 @@ 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) {
@@ -5244,10 +5245,10 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus,
 
        status = 0;
 
-       mutex_lock(hcd->address0_mutex);
-
        for (i = 0; i < PORT_INIT_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
                 */
@@ -5255,6 +5256,8 @@ 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;
                }
 
@@ -5276,13 +5279,13 @@ 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);
@@ -5372,11 +5375,14 @@ 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;
@@ -5399,8 +5405,6 @@ loop:
        }
 
 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)