[PATCH 5.13 018/104] can: usb_8dev: fix memory leak

Greg Kroah-Hartman
2021-08-02T14:07:23Z

From: Pavel Skripkin <paskripkin@gmail.com>

commit 0e865f0c31928d6a313269ef624907eec55287c4 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/can/usb/usb_8dev.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

--- 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_8de
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_8de
}

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_8de
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_8de
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_8

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);