can: usb_8dev: fix memory leak

In usb_8dev_start() MAX_RX_URBS coherent buffers are allocated and
there is nothing, that frees them:

1) In callback function the urb is resubmitted and that's all
2) In disconnect function urbs are simply killed, but URB_FREE_BUFFER
   is not set (see usb_8dev_start) and this flag cannot be used with
   coherent buffers.

So, all allocated buffers should be freed with usb_free_coherent()
explicitly.

Side note: This code looks like a copy-paste of other can drivers. The
same patch was applied to mcba_usb driver and it works nice with real
hardware. There is no change in functionality, only clean-up code for
coherent buffers.

Fixes: 0024d8ad1639 ("can: usb_8dev: Add support for USB2CAN interface from 8 devices")
Link: https://lore.kernel.org/r/d39b458cd425a1cf7f512f340224e6e9563b07bd.1627404470.git.paskripkin@gmail.com
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/usb/usb_8dev.c b/drivers/net/can/usb/usb_8dev.c
index b6e7ef0..d1b83bd 100644 (file)
--- a/drivers/net/can/usb/usb_8dev.c
+++ b/drivers/net/can/usb/usb_8dev.c
@@ -137,7 +137,8 @@ struct usb_8dev_priv {
        u8 *cmd_msg_buffer;
 
        struct mutex usb_8dev_cmd_lock;
-
+       void *rxbuf[MAX_RX_URBS];
+       dma_addr_t rxbuf_dma[MAX_RX_URBS];
 };
 
 /* tx frame */
@@ -733,6 +734,7 @@ static int usb_8dev_start(struct usb_8dev_priv *priv)
        for (i = 0; i < MAX_RX_URBS; i++) {
                struct urb *urb = NULL;
                u8 *buf;
+               dma_addr_t buf_dma;
 
                /* create a URB, and a buffer for it */
                urb = usb_alloc_urb(0, GFP_KERNEL);
@@ -742,7 +744,7 @@ static int usb_8dev_start(struct usb_8dev_priv *priv)
                }
 
                buf = usb_alloc_coherent(priv->udev, RX_BUFFER_SIZE, GFP_KERNEL,
-                                        &urb->transfer_dma);
+                                        &buf_dma);
                if (!buf) {
                        netdev_err(netdev, "No memory left for USB buffer\n");
                        usb_free_urb(urb);
@@ -750,6 +752,8 @@ static int usb_8dev_start(struct usb_8dev_priv *priv)
                        break;
                }
 
+               urb->transfer_dma = buf_dma;
+
                usb_fill_bulk_urb(urb, priv->udev,
                                  usb_rcvbulkpipe(priv->udev,
                                                  USB_8DEV_ENDP_DATA_RX),
@@ -767,6 +771,9 @@ static int usb_8dev_start(struct usb_8dev_priv *priv)
                        break;
                }
 
+               priv->rxbuf[i] = buf;
+               priv->rxbuf_dma[i] = buf_dma;
+
                /* Drop reference, USB core will take care of freeing it */
                usb_free_urb(urb);
        }
@@ -836,6 +843,10 @@ static void unlink_all_urbs(struct usb_8dev_priv *priv)
 
        usb_kill_anchored_urbs(&priv->rx_submitted);
 
+       for (i = 0; i < MAX_RX_URBS; ++i)
+               usb_free_coherent(priv->udev, RX_BUFFER_SIZE,
+                                 priv->rxbuf[i], priv->rxbuf_dma[i]);
+
        usb_kill_anchored_urbs(&priv->tx_submitted);
        atomic_set(&priv->active_tx_urbs, 0);