Commit dfc88357 authored by Michal Pecio's avatar Michal Pecio Committed by Greg Kroah-Hartman
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usb: xhci: Don't change the status of stalled TDs on failed Stop EP 



When the device stalls an endpoint, current TD is assigned -EPIPE
status and Reset Endpoint is queued. If a Stop Endpoint is pending
at the time, it will run before Reset Endpoint and fail due to the
stall. Its handler will change TD's status to -EPROTO before Reset
Endpoint handler runs and initiates giveback.

Check if the stall has already been handled and don't try to do it
again. Since xhci_handle_halted_endpoint() performs this check too,
not overwriting td->status is the only difference.

I haven't seen this case yet, but I have seen a related one where
the xHC has already executed Reset Endpoint, EP Context state is
now Stopped and EP_HALTED is set. If the xHC took a bit longer to
execute Reset Endpoint, said case would become this one.

Signed-off-by: default avatarMichal Pecio <michal.pecio@gmail.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250311154551.4035726-3-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0c74d232

drivers/usb/host/xhci-ring.c

+11 −1
Original line number Diff line number Diff line
@@ -1220,7 +1220,14 @@ static void xhci_handle_cmd_stop_ep(struct xhci_hcd *xhci, int slot_id, 
	 */

		switch (GET_EP_CTX_STATE(ep_ctx)) {

		case EP_STATE_HALTED:

			xhci_dbg(xhci, "Stop ep completion raced with stall, reset ep\n");

			xhci_dbg(xhci, "Stop ep completion raced with stall\n");

			/*

			 * If the halt happened before Stop Endpoint failed, its transfer event

			 * should have already been handled and Reset Endpoint should be pending.

			 */

			if (ep->ep_state & EP_HALTED)

				goto reset_done;



			if (ep->ep_state & EP_HAS_STREAMS) {

				reset_type = EP_SOFT_RESET;

			} else {
@@ -1231,8 +1238,11 @@ static void xhci_handle_cmd_stop_ep(struct xhci_hcd *xhci, int slot_id, 
			}

			/* reset ep, reset handler cleans up cancelled tds */

			err = xhci_handle_halted_endpoint(xhci, ep, td, reset_type);

			xhci_dbg(xhci, "Stop ep completion resetting ep, status %d\n", err);

			if (err)

				break;

reset_done:

			/* Reset EP handler will clean up cancelled TDs */

			ep->ep_state &= ~EP_STOP_CMD_PENDING;

			return;

		case EP_STATE_STOPPED: