can: esd_usb: esd_usb_read_bulk_callback(): fix URB memory leak

Fix similar memory leak as in commit 7352e1d5932a ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").

In esd_usb_open(), the URBs for USB-in transfers are allocated, added to
the dev->rx_submitted anchor and submitted. In the complete callback
esd_usb_read_bulk_callback(), the URBs are processed and resubmitted. In
esd_usb_close() the URBs are freed by calling
usb_kill_anchored_urbs(&dev->rx_submitted).

However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in esd_usb_close().

Fix the memory leak by anchoring the URB in the
esd_usb_read_bulk_callback() to the dev->rx_submitted anchor.

Fixes: 96d8e90382dc ("can: Add driver for esd CAN-USB/2 device")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260116-can_usb-fix-memory-leak-v2-2-4b8cb2915571@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
index 08da507faef4ab0cc6305e0dc4178b8b0cf1818b..8cc924c47042bc4bc2ac595833457542225e35b3 100644 (file)
--- a/drivers/net/can/usb/esd_usb.c
+++ b/drivers/net/can/usb/esd_usb.c
@@ -541,13 +541,20 @@ resubmit_urb:
                          urb->transfer_buffer, ESD_USB_RX_BUFFER_SIZE,
                          esd_usb_read_bulk_callback, dev);
 
+       usb_anchor_urb(urb, &dev->rx_submitted);
+
        err = usb_submit_urb(urb, GFP_ATOMIC);
+       if (!err)
+               return;
+
+       usb_unanchor_urb(urb);
+
        if (err == -ENODEV) {
                for (i = 0; i < dev->net_count; i++) {
                        if (dev->nets[i])
                                netif_device_detach(dev->nets[i]->netdev);
                }
-       } else if (err) {
+       } else {
                dev_err(dev->udev->dev.parent,
                        "failed resubmitting read bulk urb: %pe\n", ERR_PTR(err));
        }