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: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250311154551.4035726-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 0f8acbb9cd217a3c2d981ee4a8367d0617c2e6d4..303d66df271ea6b81a2bc19c344a525858592391 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -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: