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@xxxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
---
drivers/usb/core/hub.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 00c3506324e4..00070a8a6507 100644
--- 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 @@ 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)
--
2.25.1
