[PATCH 6.1 423/482] usb: dwc3: Remove WARN_ON for device endpoint command timeouts
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2025-08-26 13:34:38
Also in:
linux-patches
6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Selvarasu Ganesan <redacted>
commit 45eae113dccaf8e502090ecf5b3d9e9b805add6f upstream.
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 <stable@kernel.org>
Co-developed-by: Akash M <redacted>
Signed-off-by: Akash M <redacted>
Signed-off-by: Selvarasu Ganesan <redacted>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20250808125315.1607-1-selvarasu.g@samsung.com (local)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/dwc3/ep0.c | 20 ++++++++++++++++----
drivers/usb/dwc3/gadget.c | 10 ++++++++--
2 files changed, 24 insertions(+), 6 deletions(-)
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c@@ -286,7 +286,9 @@ 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;
@@ -1058,7 +1060,9 @@ static void __dwc3_ep0_do_control_data(s 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)
@@ -1075,7 +1079,12 @@ static int dwc3_ep0_start_control_status 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,
@@ -1118,7 +1127,10 @@ void dwc3_ep0_end_control_data(struct dw cmd |= DWC3_DEPCMD_PARAM(dep->resource_index); memset(¶ms, 0, sizeof(params)); ret = dwc3_send_gadget_ep_cmd(dep, cmd, ¶ms); - WARN_ON_ONCE(ret); + if (ret) + dev_err_ratelimited(dwc->dev, + "ep0 data phase end transfer failed: %d\n", ret); + dep->resource_index = 0; } --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c
@@ -1724,7 +1724,11 @@ static int __dwc3_stop_active_transfer(s 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)
@@ -3897,7 +3901,9 @@ static void dwc3_clear_stall_all_ep(stru 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); } }