[PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Selvarasu Ganesan]

This commit addresses a rarely observed endpoint command timeout
which causes kernel panic due to warn when 'panic_on_warn' is enabled
and unnecessary call trace prints when 'panic_on_warn' is disabled.
It is seen during fast software-controlled connect/disconnect testcases.
The following is one such endpoint command timeout that we observed:

1. Connect
   =======
->dwc3_thread_interrupt
 ->dwc3_ep0_interrupt
  ->configfs_composite_setup
   ->composite_setup
    ->usb_ep_queue
     ->dwc3_gadget_ep0_queue
      ->__dwc3_gadget_ep0_queue
       ->__dwc3_ep0_do_control_data
        ->dwc3_send_gadget_ep_cmd

2. Disconnect
   ==========
->dwc3_thread_interrupt
 ->dwc3_gadget_disconnect_interrupt
  ->dwc3_ep0_reset_state
   ->dwc3_ep0_end_control_data
    ->dwc3_send_gadget_ep_cmd

In the issue scenario, in Exynos platforms, we observed that control
transfers for the previous connect have not yet been completed and end
transfer command sent as a part of the disconnect sequence and
processing of USB_ENDPOINT_HALT feature request from the host timeout.
This maybe an expected scenario since the controller is processing EP
commands sent as a part of the previous connect. It maybe better to
remove WARN_ON in all places where device endpoint commands are sent to
avoid unnecessary kernel panic due to warn.

Cc: stable@vger.kernel.org
Signed-off-by: Akash M <akash.m5@samsung.com>
Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
---

Changes in v2:
- Removed the 'Fixes' tag from the commit message, as this patch does
  not contain a fix.
- And Retained the 'stable' tag, as these changes are intended to be
  applied across all stable kernels.
- Additionally, replaced 'dev_warn*' with 'dev_err*'."
Link to v1: https://lore.kernel.org/all/20250807005638.thhsgjn73aaov2af@synopsys.com/
---
 drivers/usb/dwc3/ep0.c    | 20 ++++++++++++++++----
 drivers/usb/dwc3/gadget.c | 10 ++++++++--
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 666ac432f52d..b4229aa13f37 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -288,7 +288,9 @@ void dwc3_ep0_out_start(struct dwc3 *dwc)
 	dwc3_ep0_prepare_one_trb(dep, dwc->ep0_trb_addr, 8,
 			DWC3_TRBCTL_CONTROL_SETUP, false);
 	ret = dwc3_ep0_start_trans(dep);
-	WARN_ON(ret < 0);
+	if (ret < 0)
+		dev_err(dwc->dev, "ep0 out start transfer failed: %d\n", ret);
+
 	for (i = 2; i < DWC3_ENDPOINTS_NUM; i++) {
 		struct dwc3_ep *dwc3_ep;
 
@@ -1061,7 +1063,9 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
 		ret = dwc3_ep0_start_trans(dep);
 	}
 
-	WARN_ON(ret < 0);
+	if (ret < 0)
+		dev_err(dwc->dev,
+			"ep0 data phase start transfer failed: %d\n", ret);
 }
 
 static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
@@ -1078,7 +1082,12 @@ static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
 
 static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep)
 {
-	WARN_ON(dwc3_ep0_start_control_status(dep));
+	int	ret;
+
+	ret = dwc3_ep0_start_control_status(dep);
+	if (ret)
+		dev_err(dwc->dev,
+			"ep0 status phase start transfer failed: %d\n", ret);
 }
 
 static void dwc3_ep0_do_control_status(struct dwc3 *dwc,
@@ -1121,7 +1130,10 @@ void dwc3_ep0_end_control_data(struct dwc3 *dwc, struct dwc3_ep *dep)
 	cmd |= DWC3_DEPCMD_PARAM(dep->resource_index);
 	memset(&params, 0, sizeof(params));
 	ret = dwc3_send_gadget_ep_cmd(dep, cmd, &params);
-	WARN_ON_ONCE(ret);
+	if (ret)
+		dev_err_ratelimited(dwc->dev,
+			"ep0 data phase end transfer failed: %d\n", ret);
+
 	dep->resource_index = 0;
 }
 
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 4a3e97e606d1..4a3d076c1015 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1772,7 +1772,11 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
 		dep->flags |= DWC3_EP_DELAY_STOP;
 		return 0;
 	}
-	WARN_ON_ONCE(ret);
+
+	if (ret)
+		dev_err_ratelimited(dep->dwc->dev,
+				"end transfer failed: %d\n", ret);
+
 	dep->resource_index = 0;
 
 	if (!interrupt)
@@ -4039,7 +4043,9 @@ static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)
 		dep->flags &= ~DWC3_EP_STALL;
 
 		ret = dwc3_send_clear_stall_ep_cmd(dep);
-		WARN_ON_ONCE(ret);
+		if (ret)
+			dev_err_ratelimited(dwc->dev,
+				"failed to clear STALL on %s\n", dep->name);
 	}
 }
 
-- 
2.17.1

Re: [PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Thinh Nguyen]

On Thu, Aug 07, 2025, Selvarasu Ganesan wrote:
> This commit addresses a rarely observed endpoint command timeout
> which causes kernel panic due to warn when 'panic_on_warn' is enabled
> and unnecessary call trace prints when 'panic_on_warn' is disabled.
> It is seen during fast software-controlled connect/disconnect testcases.
> The following is one such endpoint command timeout that we observed:
> 
> 1. Connect
>    =======
> ->dwc3_thread_interrupt
>  ->dwc3_ep0_interrupt
>   ->configfs_composite_setup
>    ->composite_setup
>     ->usb_ep_queue
>      ->dwc3_gadget_ep0_queue
>       ->__dwc3_gadget_ep0_queue
>        ->__dwc3_ep0_do_control_data
>         ->dwc3_send_gadget_ep_cmd
> 
> 2. Disconnect
>    ==========
> ->dwc3_thread_interrupt
>  ->dwc3_gadget_disconnect_interrupt
>   ->dwc3_ep0_reset_state
>    ->dwc3_ep0_end_control_data
>     ->dwc3_send_gadget_ep_cmd
> 
> In the issue scenario, in Exynos platforms, we observed that control
> transfers for the previous connect have not yet been completed and end
> transfer command sent as a part of the disconnect sequence and
> processing of USB_ENDPOINT_HALT feature request from the host timeout.
> This maybe an expected scenario since the controller is processing EP
> commands sent as a part of the previous connect. It maybe better to
> remove WARN_ON in all places where device endpoint commands are sent to
> avoid unnecessary kernel panic due to warn.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Akash M <akash.m5@samsung.com>
> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
> ---
> 
> Changes in v2:
> - Removed the 'Fixes' tag from the commit message, as this patch does
>   not contain a fix.
> - And Retained the 'stable' tag, as these changes are intended to be
>   applied across all stable kernels.
> - Additionally, replaced 'dev_warn*' with 'dev_err*'."
> Link to v1: https://urldefense.com/v3/__https://lore.kernel.org/all/20250807005638.thhsgjn73aaov2af@synopsys.com/__;!!A4F2R9G_pg!fGholZu_giqPUY40LREan9c7A05ec6mbjlIxrsuzsMKfOiEk8u8GsPxRlXTCaxoWM4nLboHcmzblqgQP2eSzvOqEuAY$ 
> ---
>  drivers/usb/dwc3/ep0.c    | 20 ++++++++++++++++----
>  drivers/usb/dwc3/gadget.c | 10 ++++++++--
>  2 files changed, 24 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
> index 666ac432f52d..b4229aa13f37 100644
> --- a/drivers/usb/dwc3/ep0.c
> +++ b/drivers/usb/dwc3/ep0.c
> @@ -288,7 +288,9 @@ void dwc3_ep0_out_start(struct dwc3 *dwc)
>  	dwc3_ep0_prepare_one_trb(dep, dwc->ep0_trb_addr, 8,
>  			DWC3_TRBCTL_CONTROL_SETUP, false);
>  	ret = dwc3_ep0_start_trans(dep);
> -	WARN_ON(ret < 0);
> +	if (ret < 0)
> +		dev_err(dwc->dev, "ep0 out start transfer failed: %d\n", ret);
> +
>  	for (i = 2; i < DWC3_ENDPOINTS_NUM; i++) {
>  		struct dwc3_ep *dwc3_ep;
>  
> @@ -1061,7 +1063,9 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
>  		ret = dwc3_ep0_start_trans(dep);
>  	}
>  
> -	WARN_ON(ret < 0);
> +	if (ret < 0)
> +		dev_err(dwc->dev,
> +			"ep0 data phase start transfer failed: %d\n", ret);
>  }
>  
>  static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
> @@ -1078,7 +1082,12 @@ static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
>  
>  static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep)
>  {
> -	WARN_ON(dwc3_ep0_start_control_status(dep));
> +	int	ret;
> +
> +	ret = dwc3_ep0_start_control_status(dep);
> +	if (ret)
> +		dev_err(dwc->dev,
> +			"ep0 status phase start transfer failed: %d\n", ret);
>  }
>  
>  static void dwc3_ep0_do_control_status(struct dwc3 *dwc,
> @@ -1121,7 +1130,10 @@ void dwc3_ep0_end_control_data(struct dwc3 *dwc, struct dwc3_ep *dep)
>  	cmd |= DWC3_DEPCMD_PARAM(dep->resource_index);
>  	memset(&params, 0, sizeof(params));
>  	ret = dwc3_send_gadget_ep_cmd(dep, cmd, &params);
> -	WARN_ON_ONCE(ret);
> +	if (ret)
> +		dev_err_ratelimited(dwc->dev,
> +			"ep0 data phase end transfer failed: %d\n", ret);
> +
>  	dep->resource_index = 0;
>  }
>  
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 4a3e97e606d1..4a3d076c1015 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1772,7 +1772,11 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
>  		dep->flags |= DWC3_EP_DELAY_STOP;
>  		return 0;
>  	}
> -	WARN_ON_ONCE(ret);
> +
> +	if (ret)
> +		dev_err_ratelimited(dep->dwc->dev,
> +				"end transfer failed: %d\n", ret);
> +
>  	dep->resource_index = 0;
>  
>  	if (!interrupt)
> @@ -4039,7 +4043,9 @@ static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)
>  		dep->flags &= ~DWC3_EP_STALL;
>  
>  		ret = dwc3_send_clear_stall_ep_cmd(dep);
> -		WARN_ON_ONCE(ret);
> +		if (ret)
> +			dev_err_ratelimited(dwc->dev,
> +				"failed to clear STALL on %s\n", dep->name);
>  	}
>  }
>  
> -- 
> 2.17.1
> 

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

BR,
Thinh

Re: [PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Sebastian Andrzej Siewior]

On 2025-08-07 07:16:31 [+0530], Selvarasu Ganesan wrote:
> This commit addresses a rarely observed endpoint command timeout
…
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Akash M <akash.m5@samsung.com>
> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>

The Author is Selvarasu Ganesan <selvarasu.g@samsung.com> while the
first sign-off is Akash M <akash.m5@samsung.com>. If Akash is the Author
and you are sending it then the patch body has to start with From: line
to credit this.

Please see
https://origin.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by
and https://origin.kernel.org/doc/html/latest/process/submitting-patches.html#from-line

Sebastian

Re: [PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Selvarasu Ganesan]

On 8/8/2025 2:31 PM, Sebastian Andrzej Siewior wrote:
> On 2025-08-07 07:16:31 [+0530], Selvarasu Ganesan wrote:
>> This commit addresses a rarely observed endpoint command timeout
> …
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Akash M <akash.m5@samsung.com>
>> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
> The Author is Selvarasu Ganesan <selvarasu.g@samsung.com> while the
> first sign-off is Akash M <akash.m5@samsung.com>. If Akash is the Author
> and you are sending it then the patch body has to start with From: line
> to credit this.
>
> Please see
> https://origin.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by
> and https://origin.kernel.org/doc/html/latest/process/submitting-patches.html#from-line
>
> Sebastian


Hi Sebastian,

Thank you for pointing out the discrepancy. We will ensure that the 
patch submission accurately reflects the authorship.

Since I, "Selvarasu Ganesan" am the author, I will reorder the sign-offs 
to reflect the correct authorship.

Here is the corrected patch submission:

Cc: stable@vger.kernel.org
Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
Signed-off-by: Akash M <akash.m5@samsung.com>

Regarding the next steps, I will post a new patchset with the reordered 
sign-offs.

Thanks,
Selva

Re: [PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Sebastian Andrzej Siewior]

On 2025-08-08 16:07:25 [+0530], Selvarasu Ganesan wrote:
> Thank you for pointing out the discrepancy. We will ensure that the 
> patch submission accurately reflects the authorship.
> 
> Since I, "Selvarasu Ganesan" am the author, I will reorder the sign-offs 
> to reflect the correct authorship.
> 
> Here is the corrected patch submission:
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
> Signed-off-by: Akash M <akash.m5@samsung.com>
> 
> Regarding the next steps, I will post a new patchset with the reordered 
> sign-offs.

Your sign-off (as the poster) should come last.
What is Akash' role in this?

> Thanks,
> Selva

Sebastian

Re: [PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Selvarasu Ganesan]

On 8/8/2025 4:22 PM, Sebastian Andrzej Siewior wrote:
> On 2025-08-08 16:07:25 [+0530], Selvarasu Ganesan wrote:
>> Thank you for pointing out the discrepancy. We will ensure that the
>> patch submission accurately reflects the authorship.
>>
>> Since I, "Selvarasu Ganesan" am the author, I will reorder the sign-offs
>> to reflect the correct authorship.
>>
>> Here is the corrected patch submission:
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
>> Signed-off-by: Akash M <akash.m5@samsung.com>
>>
>> Regarding the next steps, I will post a new patchset with the reordered
>> sign-offs.
> Your sign-off (as the poster) should come last.
> What is Akash' role in this?


Akash M's role in the patch as a co-contributor.
Shall i add tag as Co-developed-by: Akash M <akash.m5@samsung.com>?

Cc: stable@vger.kernel.org
Co-developed-by: Akash M <akash.m5@samsung.com>
Signed-off-by: Akash M <akash.m5@samsung.com>
Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>


>> Thanks,
>> Selva
> Sebastian
>
>

Re: [PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Sebastian Andrzej Siewior]

On 2025-08-08 16:59:08 [+0530], Selvarasu Ganesan wrote:
> >> Here is the corrected patch submission:
> >>
> >> Cc: stable@vger.kernel.org
> >> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
> >> Signed-off-by: Akash M <akash.m5@samsung.com>
> >>
> >> Regarding the next steps, I will post a new patchset with the reordered
> >> sign-offs.
> > Your sign-off (as the poster) should come last.
> > What is Akash' role in this?
> 
> 
> Akash M's role in the patch as a co-contributor.
> Shall i add tag as Co-developed-by: Akash M <akash.m5@samsung.com>?
> 
> Cc: stable@vger.kernel.org
> Co-developed-by: Akash M <akash.m5@samsung.com>
> Signed-off-by: Akash M <akash.m5@samsung.com>
> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>

Yes. This looks good now.

> >> Thanks,
> >> Selva

Sebastian

Re: [PATCH v2] usb: dwc3: Remove WARN_ON for device endpoint command timeouts

[Selvarasu Ganesan]

On 8/8/2025 6:13 PM, Sebastian Andrzej Siewior wrote:
> On 2025-08-08 16:59:08 [+0530], Selvarasu Ganesan wrote:
>>>> Here is the corrected patch submission:
>>>>
>>>> Cc: stable@vger.kernel.org
>>>> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
>>>> Signed-off-by: Akash M <akash.m5@samsung.com>
>>>>
>>>> Regarding the next steps, I will post a new patchset with the reordered
>>>> sign-offs.
>>> Your sign-off (as the poster) should come last.
>>> What is Akash' role in this?
>>
>> Akash M's role in the patch as a co-contributor.
>> Shall i add tag as Co-developed-by: Akash M <akash.m5@samsung.com>?
>>
>> Cc: stable@vger.kernel.org
>> Co-developed-by: Akash M <akash.m5@samsung.com>
>> Signed-off-by: Akash M <akash.m5@samsung.com>
>> Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
> Yes. This looks good now.
Ok. Thanks for the confirmation.
>
>>>> Thanks,
>>>> Selva
> Sebastian
>
>