Hi,
On 11/22/21 11:50, Mathias Nyman wrote:
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 Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com
Oh, this is great, with this patch I can finally hot-plug my thunderbolt dock (and thus a XHCI controller) without the XHCI controller given a whole bunch of weird errors (and some USB devices not working), which it does not when already connected at boot.
I also tried the hotplug thingy with the previous fix without this locking fix and then I actually hit the deadlock and things like lsusb would hang.
If we can get these 2 fixes together merged soon and also backported to the stable series that would be great:
Acked-by: Hans de Goede hdegoede@redhat.com Tested-by: Hans de Goede hdegoede@redhat.com
Regards,
Hans
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;*/
- 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);usb_unlock_port(port_dev);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);}@@ -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)