On Tue, Jun 18, 2024 at 8:35 AM Li, Meng <meng...@windriver.com> wrote:
>
>
>
> > -----Original Message-----
> > From: linux-yocto@lists.yoctoproject.org
> > <linux-yocto@lists.yoctoproject.org>
> > On Behalf Of Bruce Ashfield
> > Sent: Tuesday, June 18, 2024 8:29 PM
> > To: Li, Meng <meng...@windriver.com>
> > Cc: linux-yocto@lists.yoctoproject.org
> > Subject: Re: [linux-yocto] [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 at 12:02 AM Meng Li <meng...@windriver.com> 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.
> > >
> >
> > I'll apply this to v6.6/standard/base and linux-yocto-dev
> > v6.10/standard/base.
> >
>
> This patch works fine for v6.6/standard/base.
> About the v6.10/standard/base branch, there is code context conflict.
I assume that the maintainers patch or other changes are protecting
6.10 from the issue ?
>
> > Correct me if I'm wrong and you'd still prefer it on the BSP branches.
> >
>
> Yes! I would like to it on BSP branches, too.
This is now merged. Whenever something goes to standard/base, it will
always be on all BSPs as well since my scripts merge from the core
branches to all BSP leaf branches on every change.
Bruce
>
> Thanks,
> Limeng
>
> > Bruce
> >
> > > Fixes: 5265397f9442 ("usb: dwc3: Remove DWC3 locking during gadget
> > > suspend/resume")
> > > Cc: Xu Yang <xu.yan...@nxp.com>
> > > Cc: sta...@vger.kernel.org
> > > Signed-off-by: Meng Li <meng...@windriver.com>
> > > ---
> > > 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
> > > a8fb10cc65bc..9bb4ab409bbb 100644
> > > --- a/drivers/usb/dwc3/core.c
> > > +++ b/drivers/usb/dwc3/core.c
> > > @@ -2112,7 +2112,6 @@ 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;
> > >
> > > switch (dwc->current_dr_role) { @@ -2150,9 +2149,7 @@ 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);
> > > }
> > >
> > > @@ -2169,7 +2166,6 @@ 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;
> > >
> > > @@ -2227,9 +2223,7 @@ 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
> > >
> >
> >
> > --
> > - Thou shalt not follow the NULL pointer, for chaos and madness await thee
> > at
> > its end
> > - "Use the force Harry" - Gandalf, Star Trek II
--
- Thou shalt not follow the NULL pointer, for chaos and madness await
thee at its end
- "Use the force Harry" - Gandalf, Star Trek II
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