[PATCH 4.4 17/26] can: esd_usb2: fix memory leak

Greg Kroah-Hartman
2021-08-02T13:48:28Z

From: Pavel Skripkin <paskripkin@gmail.com>

commit 928150fad41ba16df7fcc9f7f945747d0f56cbb6 upstream.

In esd_usb2_setup_rx_urbs() 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 esd_usb2_setup_rx_urbs) 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: 96d8e90382dc ("can: Add driver for esd CAN-USB/2 device")
Link: https://lore.kernel.org/r/b31b096926dcb35998ad0271aac4b51770ca7cc8.1627404470.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/esd_usb2.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)

--- a/drivers/net/can/usb/esd_usb2.c
+++ b/drivers/net/can/usb/esd_usb2.c
@@ -207,6 +207,8 @@ struct esd_usb2 {
int net_count;
u32 version;
int rxinitdone;
+ void *rxbuf[MAX_RX_URBS];
+ dma_addr_t rxbuf_dma[MAX_RX_URBS];
};

struct esd_usb2_net_priv {
@@ -556,6 +558,7 @@ static int esd_usb2_setup_rx_urbs(struct
for (i = 0; i < MAX_RX_URBS; i++) {
struct urb *urb = NULL;
u8 *buf = NULL;
+ dma_addr_t buf_dma;

/* create a URB, and a buffer for it */
urb = usb_alloc_urb(0, GFP_KERNEL);
@@ -567,7 +570,7 @@ static int esd_usb2_setup_rx_urbs(struct
}

buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
- &urb->transfer_dma);
+ &buf_dma);
if (!buf) {
dev_warn(dev->udev->dev.parent,
"No memory left for USB buffer\n");
@@ -575,6 +578,8 @@ static int esd_usb2_setup_rx_urbs(struct
goto freeurb;
}

+ urb->transfer_dma = buf_dma;
+
usb_fill_bulk_urb(urb, dev->udev,
usb_rcvbulkpipe(dev->udev, 1),
buf, RX_BUFFER_SIZE,
@@ -587,8 +592,12 @@ static int esd_usb2_setup_rx_urbs(struct
usb_unanchor_urb(urb);
usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
urb->transfer_dma);
+ goto freeurb;
}

+ dev->rxbuf[i] = buf;
+ dev->rxbuf_dma[i] = buf_dma;
+
freeurb:
/* Drop reference, USB core will take care of freeing it */
usb_free_urb(urb);
@@ -676,6 +685,11 @@ static void unlink_all_urbs(struct esd_u
int i, j;

usb_kill_anchored_urbs(&dev->rx_submitted);
+
+ for (i = 0; i < MAX_RX_URBS; ++i)
+ usb_free_coherent(dev->udev, RX_BUFFER_SIZE,
+ dev->rxbuf[i], dev->rxbuf_dma[i]);
+
for (i = 0; i < dev->net_count; i++) {
priv = dev->nets[i];
if (priv) {