usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

When config CONFIG_USB_DWC3_DUAL_ROLE is selected, and trigger system
to enter suspend status with below command:
echo mem > /sys/power/state
There will be a deadlock issue occurring. Detailed invoking path as
below:
dwc3_suspend_common()
    spin_lock_irqsave(&dwc->lock, flags);              <-- 1st
    dwc3_gadget_suspend(dwc);
        dwc3_gadget_soft_disconnect(dwc);
            spin_lock_irqsave(&dwc->lock, flags);      <-- 2nd
This issue is exposed by commit c7ebd8149ee5 ("usb: dwc3: gadget: Fix
NULL pointer dereference in dwc3_gadget_suspend") that removes the code
of checking whether dwc->gadget_driver is NULL or not. It causes the
following code is executed and deadlock occurs when trying to get the
spinlock. In fact, the root cause is the commit 5265397f9442("usb: dwc3:
Remove DWC3 locking during gadget suspend/resume") that forgot to remove
the lock of otg mode. So, remove the redundant lock of otg mode during
gadget suspend/resume.

Fixes: 5265397f9442 ("usb: dwc3: Remove DWC3 locking during gadget suspend/resume")
Cc: Xu Yang <xu.yang_2@nxp.com>
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20240618031918.2585799-1-Meng.Li@windriver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 7ee61a89520b695ff476844834d139851aa74f25..9d47c3aa57771093d1f604f946abaf8f91d5fcf7 100644 (file)
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -2250,7 +2250,6 @@ assert_reset:
 
 static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 {
-       unsigned long   flags;
        u32 reg;
        int i;
 
@@ -2293,9 +2292,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
                        break;
 
                if (dwc->current_otg_role == DWC3_OTG_ROLE_DEVICE) {
-                       spin_lock_irqsave(&dwc->lock, flags);
                        dwc3_gadget_suspend(dwc);
-                       spin_unlock_irqrestore(&dwc->lock, flags);
                        synchronize_irq(dwc->irq_gadget);
                }
 
@@ -2312,7 +2309,6 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 
 static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
 {
-       unsigned long   flags;
        int             ret;
        u32             reg;
        int             i;
@@ -2366,9 +2362,7 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
                if (dwc->current_otg_role == DWC3_OTG_ROLE_HOST) {
                        dwc3_otg_host_init(dwc);
                } else if (dwc->current_otg_role == DWC3_OTG_ROLE_DEVICE) {
-                       spin_lock_irqsave(&dwc->lock, flags);
                        dwc3_gadget_resume(dwc);
-                       spin_unlock_irqrestore(&dwc->lock, flags);
                }
 
                break;