[v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Meng Li]

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>

---
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

Re: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Thinh Nguyen]

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@nxp.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Meng Li <Meng.Li@windriver.com>
> 
> ---
> 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,

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

Thanks,
Thinh

Re: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Michael Nazzareno Trimarchi]

Hi

On Tue, Jun 18, 2024 at 11:55 PM Thinh Nguyen <Thinh.Nguyen@synopsys.com> wrote:
>
> 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


In resume path the spinlock was taken too and I see that there is a call
dwc3_gadget_soft_connect that call the dwc3_core_soft_reset that can poll
using msleep for time.  I don't know if this is a valid fix but seems
does not fix
only commit c7ebd8149ee5

Michael

> > 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>
> >
> > ---
> > 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,
>
> Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
>
> Thanks,
> Thinh

Re: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Thinh Nguyen]

Hi,

On Wed, Jun 19, 2024, Michael Nazzareno Trimarchi wrote:
> Hi
> 
> On Tue, Jun 18, 2024 at 11:55 PM Thinh Nguyen <Thinh.Nguyen@synopsys.com> wrote:
> >
> > 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
> 
> 
> In resume path the spinlock was taken too and I see that there is a call
> dwc3_gadget_soft_connect that call the dwc3_core_soft_reset that can poll
> using msleep for time.  I don't know if this is a valid fix but seems
> does not fix
> only commit c7ebd8149ee5
> 

Meng did take the resume path into account. Can you clarify what you
meant with "does not fix only commit c7ebd8149ee5"?

Thanks,
Thinh

> 
> > > 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>
> > >
> > > ---
> > > 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,
> >
> > Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> >
> > Thanks,
> > Thinh

Re: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Michael Nazzareno Trimarchi]

Hi

On Wed, Jun 19, 2024 at 12:42 AM Thinh Nguyen <Thinh.Nguyen@synopsys.com> wrote:
>
> Hi,
>
> On Wed, Jun 19, 2024, Michael Nazzareno Trimarchi wrote:
> > Hi
> >
> > On Tue, Jun 18, 2024 at 11:55 PM Thinh Nguyen <Thinh.Nguyen@synopsys.com> wrote:
> > >
> > > 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
> >
> >
> > In resume path the spinlock was taken too and I see that there is a call
> > dwc3_gadget_soft_connect that call the dwc3_core_soft_reset that can poll
> > using msleep for time.  I don't know if this is a valid fix but seems
> > does not fix
> > only commit c7ebd8149ee5
> >
>
> Meng did take the resume path into account. Can you clarify what you
> meant with "does not fix only commit c7ebd8149ee5"?

I have seen that is suppose to fix something introduced by that commit
but I think
that resume path was already broken before

spinlock_irqsave()
dwc3_gadget_resume -> dwc3_gadget_soft_connect -> dwc3_core_soft_reset
(can sleep)

Michael
>
> Thanks,
> Thinh
>
> >
> > > > 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>
> > > >
> > > > ---
> > > > 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,
> > >
> > > Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> > >
> > > Thanks,
> > > Thinh



-- 
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael@amarulasolutions.com
__________________________________

Amarula Solutions BV
Joop Geesinkweg 125, 1114 AB, Amsterdam, NL
T. +31 (0)85 111 9172
info@amarulasolutions.com
www.amarulasolutions.com

Re: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Thinh Nguyen]

On Wed, Jun 19, 2024, Michael Nazzareno Trimarchi wrote:
> Hi
> 
> On Wed, Jun 19, 2024 at 12:42 AM Thinh Nguyen <Thinh.Nguyen@synopsys.com> wrote:
> >
> > Hi,
> >
> > On Wed, Jun 19, 2024, Michael Nazzareno Trimarchi wrote:
> > > Hi
> > >
> > > On Tue, Jun 18, 2024 at 11:55 PM Thinh Nguyen <Thinh.Nguyen@synopsys.com> wrote:
> > > >
> > > > 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
> > >
> > >
> > > In resume path the spinlock was taken too and I see that there is a call
> > > dwc3_gadget_soft_connect that call the dwc3_core_soft_reset that can poll
> > > using msleep for time.  I don't know if this is a valid fix but seems
> > > does not fix
> > > only commit c7ebd8149ee5
> > >
> >
> > Meng did take the resume path into account. Can you clarify what you
> > meant with "does not fix only commit c7ebd8149ee5"?
> 
> I have seen that is suppose to fix something introduced by that commit
> but I think
> that resume path was already broken before
> 
> spinlock_irqsave()
> dwc3_gadget_resume -> dwc3_gadget_soft_connect -> dwc3_core_soft_reset
> (can sleep)
> 

The code path for OTG should not hit that sleep. The sleep is only
applicable to DWC_usb31 and DWC_usb32. Technically, it wasn't broken
before. But we should remove this spinlock on resume as it is done here.

BR,
Thinh

RE: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Li, Meng]

> -----Original Message-----
> From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> Sent: Wednesday, June 19, 2024 5:54 AM
> To: Li, Meng <Meng.Li@windriver.com>
> Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>;
> gregkh@linuxfoundation.org; quic_uaggarwa@quicinc.com; linux-
> usb@vger.kernel.org; linux-kernel@vger.kernel.org; xu.yang_2@nxp.com
> 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@nxp.com>
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Meng Li <Meng.Li@windriver.com>
> >
> > ---
> > 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@synopsys.com>
> 
> Thanks,
> Thinh

RE: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Li, Meng]

> -----Original Message-----
> From: Li, Meng
> Sent: Wednesday, June 19, 2024 9:49 AM
> To: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> Cc: gregkh@linuxfoundation.org; quic_uaggarwa@quicinc.com; linux-
> usb@vger.kernel.org; linux-kernel@vger.kernel.org; xu.yang_2@nxp.com
> Subject: RE: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during
> gadget suspend/resume to avoid deadlock
> 
> 
> 
> > -----Original Message-----
> > From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> > Sent: Wednesday, June 19, 2024 5:54 AM
> > To: Li, Meng <Meng.Li@windriver.com>
> > Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>;
> > gregkh@linuxfoundation.org; quic_uaggarwa@quicinc.com; linux-
> > usb@vger.kernel.org; linux-kernel@vger.kernel.org; xu.yang_2@nxp.com
> > 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@nxp.com>
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Meng Li <Meng.Li@windriver.com>
> > >
> > > ---
> > > 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
> 

Do I need to send another v3 pull request?

Thanks,
LImeng

> > Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> >
> > Thanks,
> > Thinh

Re: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Thinh Nguyen]

On Wed, Jun 19, 2024, Li, Meng wrote:
> 
> Do I need to send another v3 pull request?
> 

No. Greg already picked this up.

Thanks,
Thinh

RE: [v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock

[Li, Meng]

> -----Original Message-----
> From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> Sent: Saturday, June 22, 2024 7:15 AM
> To: Li, Meng <Meng.Li@windriver.com>
> Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>;
> gregkh@linuxfoundation.org; quic_uaggarwa@quicinc.com; linux-
> usb@vger.kernel.org; linux-kernel@vger.kernel.org; xu.yang_2@nxp.com
> 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 Wed, Jun 19, 2024, Li, Meng wrote:
> >
> > Do I need to send another v3 pull request?
> >
> 
> No. Greg already picked this up.
> 

Thanks for reviewing and accepting my patch.
You have given me great enthusiasm to contribute to the community

regards,
Limeng

> Thanks,
> Thinh