> -----Original Message----- > From: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> > Sent: Wednesday, June 19, 2024 5:54 AM > To: Li, Meng <Meng.Li@xxxxxxxxxxxxx> > Cc: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>; > gregkh@xxxxxxxxxxxxxxxxxxx; quic_uaggarwa@xxxxxxxxxxx; linux- > usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; xu.yang_2@xxxxxxx > Subject: Re: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during > gadget suspend/resume to avoid deadlock > > CAUTION: This email comes from a non Wind River email account! > Do not click links or open attachments unless you recognize the sender and > know the content is safe. > > On Tue, Jun 18, 2024, Meng Li wrote: > > 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> > > > > --- > > v1->v2: > > - improve commit log, correct the Fixes commit id. > > > > --- > > drivers/usb/dwc3/core.c | 6 ------ > > 1 file changed, 6 deletions(-) > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index > > 7ee61a89520b..9d47c3aa5777 100644 > > --- a/drivers/usb/dwc3/core.c > > +++ b/drivers/usb/dwc3/core.c > > @@ -2250,7 +2250,6 @@ static int dwc3_core_init_for_resume(struct > dwc3 > > *dwc) > > > > 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; > > -- > > 2.34.1 > > > > Did you use "git format-patch -v"? The $subject version prefix order is > different. In any case, > Sorry! I use --subject-prefix="v2 PATCH". I will correct it in next patch pull request. Thanks, Limeng > Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> > > Thanks, > Thinh