[PATCH 6.1 087/128] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Meng Li <Meng.Li@xxxxxxxxxxxxx>

commit 7838de15bb700c2898a7d741db9b1f3cbc86c136 upstream.

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@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Meng Li <Meng.Li@xxxxxxxxxxxxx>
Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240618031918.2585799-1-Meng.Li@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/usb/dwc3/core.c |    6 ------
 1 file changed, 6 deletions(-)

--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -2087,7 +2087,6 @@ assert_reset:
 
 static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 {
-	unsigned long	flags;
 	u32 reg;
 
 	switch (dwc->current_dr_role) {
@@ -2125,9 +2124,7 @@ static int dwc3_suspend_common(struct dw
 			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);
 		}
 
@@ -2144,7 +2141,6 @@ static int dwc3_suspend_common(struct dw
 
 static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
 {
-	unsigned long	flags;
 	int		ret;
 	u32		reg;
 
@@ -2193,9 +2189,7 @@ static int dwc3_resume_common(struct dwc
 		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;