On 20-07-08 13:33:56, Jun Li wrote:
Hi,
-----Original Message----- From: Peter Chen peter.chen@nxp.com Sent: Wednesday, July 8, 2020 5:31 PM To: balbi@kernel.org; gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org; dl-linux-imx linux-imx@nxp.com; pawell@cadence.com; rogerq@ti.com; Jun Li jun.li@nxp.com; Peter Chen peter.chen@nxp.com; stable stable@vger.kernel.org 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?
Oh, my oops. This patch is based on my PM patch set which delete the gadget_dev->lock protect at cdns3_suspend, please skip it.
Peter
Cc: stable stable@vger.kernel.org Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver") Signed-off-by: Peter Chen peter.chen@nxp.com
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);spin_lock(&priv_dev->lock);-- 2.17.1