can: gs_usb: gs_usb_receive_bulk_callback(): unanchor URL on usb_submit_urb() error

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>

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index d093babbc3201ba926c4bbb7f3141699b297d646..192338b481f21f279f4b4d636652e5e4a47bdb12 100644 (file)
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -754,6 +754,10 @@ resubmit_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 @@ device_detach:
                        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));
        }
 }