On 8/6/2025 5:08 AM, Thinh Nguyen wrote:

On Mon, Aug 04, 2025, Selvarasu Ganesan wrote:

...

From: Akash M akash.m5@samsung.com

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.

Fixes: e192cc7b5239 ("usb: dwc3: gadget: move cmd_endtransfer to extra function") Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver") Fixes: c7fcdeb2627c ("usb: dwc3: ep0: simplify EP0 state machine") Fixes: f0f2b2a2db85 ("usb: dwc3: ep0: push ep0state into xfernotready processing") Fixes: 2e3db064855a ("usb: dwc3: ep0: drop XferNotReady(DATA) support") Cc: stable@vger.kernel.org

I don't think this is a fix patch. You're just replacing WARN* with dev_warn* without doing any recovery. Let's remove the Fixes and table tag. Also, can we replace dev_warn* with dev_err* because these are critical errors that may put the controller in a bad state.

Thanks, Thinh

Hi Thinh,

Thanks for your review comments. Yeah we agree. This is not a fix patch. Sure we will update new patchset with replace dev_warn* with dev_err*.

As for dropping the stable tag,  It would be better these changes to be applied across all stable kernels, so shall we keep stable tag in place?

Thanks, Selva

...

Signed-off-by: Akash M akash.m5@samsung.com Signed-off-by: Selvarasu Ganesan selvarasu.g@samsung.com diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index 666ac432f52d..7b313836f62b 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_warn(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_warn(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_warn(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_warn_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 321361288935..50e4f667b2f2 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1774,7 +1774,11 @@ 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_warn_ratelimited(dep->dwc->dev,
  

• 		"end transfer failed: ret = %d\n", ret);
  

• dep->resource_index = 0;

if (!interrupt) @@ -4041,7 +4045,9 @@ 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_warn_ratelimited(dwc->dev,
  

• 		"failed to clear STALL on %s\n", dep->name);
  

  } }

2.17.1