1. Patchew
  2. linux
  3. View series

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

Meng Li posted 1 patch 1 year, 6 months ago 
drivers/usb/dwc3/core.c | 6 ------
1 file changed, 6 deletions(-)
[v2 PATCH] usb: dwc3: core: remove lock of otg mode during gadget suspend/resume to avoid deadlock
Posted by Meng Li 1 year, 6 months ago 
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
Posted by Thinh Nguyen 1 year, 6 months ago 
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
Posted by Michael Nazzareno Trimarchi 1 year, 6 months ago 
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

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.