diff mbox series

[v2,2/3] usb: cdns3: gadget: own the lock wrongly at the suspend routine

Message ID 20201022005505.24167-3-peter.chen@nxp.com (mailing list archive)
State New, archived
Headers show
Series usb: cdns3: three bug fixes for v5.10 | expand

Commit Message

Peter Chen Oct. 22, 2020, 12:55 a.m. UTC
When the system goes to suspend, if the controller is at device mode with
cable connecting to host, the call stack is: cdns3_suspend->
cdns3_gadget_suspend -> cdns3_disconnect_gadget, after cdns3_disconnect_gadget
is called, it owns lock wrongly, it causes the system being deadlock after
resume due to at cdns3_device_thread_irq_handler, it tries to get the lock,
but can't get it forever.

To fix it, we delete the unlock-lock operations at cdns3_disconnect_gadget,
and do it at the caller.

Fixes: b1234e3b3b26 ("usb: cdns3: add runtime PM support")
Signed-off-by: Peter Chen <peter.chen@nxp.com>
---
 drivers/usb/cdns3/gadget.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Felipe Balbi Oct. 27, 2020, 9:26 a.m. UTC | #1
Peter Chen <peter.chen@nxp.com> writes:

> When the system goes to suspend, if the controller is at device mode with
> cable connecting to host, the call stack is: cdns3_suspend->
> cdns3_gadget_suspend -> cdns3_disconnect_gadget, after cdns3_disconnect_gadget
> is called, it owns lock wrongly, it causes the system being deadlock after
> resume due to at cdns3_device_thread_irq_handler, it tries to get the lock,
> but can't get it forever.
>
> To fix it, we delete the unlock-lock operations at cdns3_disconnect_gadget,
> and do it at the caller.
>
> Fixes: b1234e3b3b26 ("usb: cdns3: add runtime PM support")
> Signed-off-by: Peter Chen <peter.chen@nxp.com>

comment from previous thread is still valid. Missing __releases() and
__acquires() annotation.
Peter Chen Oct. 29, 2020, 9:31 a.m. UTC | #2
On 20-10-27 11:26:56, Felipe Balbi wrote:
> Peter Chen <peter.chen@nxp.com> writes:
> 
> > When the system goes to suspend, if the controller is at device mode with
> > cable connecting to host, the call stack is: cdns3_suspend->
> > cdns3_gadget_suspend -> cdns3_disconnect_gadget, after cdns3_disconnect_gadget
> > is called, it owns lock wrongly, it causes the system being deadlock after
> > resume due to at cdns3_device_thread_irq_handler, it tries to get the lock,
> > but can't get it forever.
> >
> > To fix it, we delete the unlock-lock operations at cdns3_disconnect_gadget,
> > and do it at the caller.
> >
> > Fixes: b1234e3b3b26 ("usb: cdns3: add runtime PM support")
> > Signed-off-by: Peter Chen <peter.chen@nxp.com>
> 
> comment from previous thread is still valid. Missing __releases() and
> __acquires() annotation.
> 

Thanks, will add __must_hold sparse checker
diff mbox series

Patch

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 6ff3aa3db497..c127af6c0fe8 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -1744,11 +1744,8 @@  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);
-	}
 }
 
 /**
@@ -1783,7 +1780,9 @@  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);
+		spin_lock(&priv_dev->lock);
 		priv_dev->gadget.speed = USB_SPEED_UNKNOWN;
 		usb_gadget_set_state(&priv_dev->gadget, USB_STATE_NOTATTACHED);
 		cdns3_hw_reset_eps_config(priv_dev);
@@ -3266,7 +3265,9 @@  static int cdns3_gadget_suspend(struct cdns3 *cdns, bool do_wakeup)
 {
 	struct cdns3_device *priv_dev = cdns->gadget_dev;
 
+	spin_unlock(&cdns->lock);
 	cdns3_disconnect_gadget(priv_dev);
+	spin_lock(&cdns->lock);
 
 	priv_dev->gadget.speed = USB_SPEED_UNKNOWN;
 	usb_gadget_set_state(&priv_dev->gadget, USB_STATE_NOTATTACHED);