[PATCH net 2/7] can: gs_usb: gs_usb_receive_bulk_callback(): unanchor URL on usb_submit_urb() error

[Marc Kleine-Budde <mkl@pengutronix.de>]

In commit 7352e1d5932a ("can: gs_usb: gs_usb_receive_bulk_callback(): fix
URB memory leak"), the URB was re-anchored before usb_submit_urb() in
gs_usb_receive_bulk_callback() to prevent a leak of this URB during
cleanup.

However, this patch did not take into account that usb_submit_urb() could
fail. The URB remains anchored and
usb_kill_anchored_urbs(&parent->rx_submitted) in gs_can_close() loops
infinitely since the anchor list never becomes empty.

To fix the bug, unanchor the URB when an usb_submit_urb() error occurs,
also print an info message.

Fixes: 7352e1d5932a ("can: gs_usb: gs_usb_receive_bulk_callback(): fix URB memory leak")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://lore.kernel.org/all/20260110223836.3890248-1-kuba@kernel.org/
Link: https://patch.msgid.link/20260116-can_usb-fix-reanchor-v1-1-9d74e7289225@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/usb/gs_usb.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index d093babbc320..192338b481f2 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -754,6 +754,10 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 	usb_anchor_urb(urb, &parent->rx_submitted);
 
 	rc = usb_submit_urb(urb, GFP_ATOMIC);
+	if (!rc)
+		return;
+
+	usb_unanchor_urb(urb);
 
 	/* USB failure take down all interfaces */
 	if (rc == -ENODEV) {
@@ -762,6 +766,9 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 			if (parent->canch[rc])
 				netif_device_detach(parent->canch[rc]->netdev);
 		}
+	} else if (rc != -ESHUTDOWN && net_ratelimit()) {
+		netdev_info(netdev, "failed to re-submit IN URB: %pe\n",
+			    ERR_PTR(urb->status));
 	}
 }
 
-- 
2.51.0