Hi,
> -----Original Message-----
> From: Peter Chen <peter.chen@xxxxxxx>
> Sent: Wednesday, July 8, 2020 5:31 PM
> To: balbi@xxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx
> Cc: linux-usb@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> pawell@xxxxxxxxxxx; rogerq@xxxxxx; Jun Li <jun.li@xxxxxxx>; Peter Chen
> <peter.chen@xxxxxxx>; stable <stable@xxxxxxxxxxxxxxx>
> Subject: [PATCH 1/1] usb: cdns3: gadget: own the lock wrongly at the suspend routine
>
> When it is device mode with cable connected to host, the call stack is:
> cdns3_suspend->cdns3_gadget_suspend->cdns3_disconnect_gadget,
> the cdns3_disconnect_gadget owns lock wrongly at this situation, it causes the
Isn't afterwards the lock will be released in cdns3_suspend() by below code?
spin_unlock_irqrestore(&cdns->gadget_dev->lock, flags);
> system being deadlock after resume due to at cdns3_device_thread_irq_handler, it
> tries to get the lock, but will never get it.
>
> To fix it, we delete the lock operations, and add them at the caller when necessary.
There are 2 caller places, by this, another code path:
cdns3_suspend->cdns3_gadget_suspend->cdns3_disconnect_gadget() will do
gadget_driver->disconnect() with lock hold, is this intentional?
Thanks
Li Jun
>
> Cc: stable <stable@xxxxxxxxxxxxxxx>
> Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
> Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
> ---
> drivers/usb/cdns3/gadget.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c index
> 13027ce6bed8..f6c51cc924a8 100644
> --- a/drivers/usb/cdns3/gadget.c
> +++ b/drivers/usb/cdns3/gadget.c
> @@ -1674,11 +1674,8 @@ static int cdns3_check_ep_interrupt_proceed(struct
> cdns3_endpoint *priv_ep)
>
> static void cdns3_disconnect_gadget(struct cdns3_device *priv_dev) {
> - if (priv_dev->gadget_driver && priv_dev->gadget_driver->disconnect) {
> - spin_unlock(&priv_dev->lock);
> + if (priv_dev->gadget_driver && priv_dev->gadget_driver->disconnect)
> priv_dev->gadget_driver->disconnect(&priv_dev->gadget);
> - spin_lock(&priv_dev->lock);
> - }
> }
>
> /**
> @@ -1713,8 +1710,10 @@ static void cdns3_check_usb_interrupt_proceed(struct
> cdns3_device *priv_dev,
>
> /* Disconnection detected */
> if (usb_ists & (USB_ISTS_DIS2I | USB_ISTS_DISI)) {
> + spin_unlock(&priv_dev->lock);
> cdns3_disconnect_gadget(priv_dev);
> priv_dev->gadget.speed = USB_SPEED_UNKNOWN;
> + spin_lock(&priv_dev->lock);
> usb_gadget_set_state(&priv_dev->gadget, USB_STATE_NOTATTACHED);
> cdns3_hw_reset_eps_config(priv_dev);
> }
> --
> 2.17.1
