From: Rhett Aultman rhett.aultman@samsara.com

The gs_usb driver appears to suffer from a malady common to many USB CAN adapter drivers in that it performs usb_alloc_coherent() to allocate a number of USB request blocks (URBs) for RX, and then later relies on usb_kill_anchored_urbs() to free them, but this doesn't actually free them. As a result, this may be leaking DMA memory that's been used by the driver.

This commit is an adaptation of the techniques found in the esd_usb2 driver where a similar design pattern led to a memory leak. It explicitly frees the RX URBs and their DMA memory via a call to usb_free_coherent(). Since the RX URBs were allocated in the gs_can_open(), we remove them in gs_can_close() rather than in the disconnect function as was done in esd_usb2.

For more information, see the 928150fad41b ("can: esd_usb2: fix memory leak").

Link: https://lore.kernel.org/all/alpine.DEB.2.22.394.2206031547001.1630869@thelap... Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices") Cc: stable@vger.kernel.org Signed-off-by: Rhett Aultman rhett.aultman@samsara.com Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- drivers/net/can/usb/gs_usb.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c index b29ba9138866..d3a658b444b5 100644 --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c @@ -268,6 +268,8 @@ struct gs_can {

struct usb_anchor tx_submitted; atomic_t active_tx_urbs; + void *rxbuf[GS_MAX_RX_URBS]; + dma_addr_t rxbuf_dma[GS_MAX_RX_URBS]; };

/* usb interface struct */ @@ -742,6 +744,7 @@ static int gs_can_open(struct net_device *netdev) for (i = 0; i < GS_MAX_RX_URBS; i++) { struct urb *urb; u8 *buf; + dma_addr_t buf_dma;

/* alloc rx urb */ urb = usb_alloc_urb(0, GFP_KERNEL); @@ -752,7 +755,7 @@ static int gs_can_open(struct net_device *netdev) buf = usb_alloc_coherent(dev->udev, dev->parent->hf_size_rx, GFP_KERNEL, - &urb->transfer_dma); + &buf_dma); if (!buf) { netdev_err(netdev, "No memory left for USB buffer\n"); @@ -760,6 +763,8 @@ static int gs_can_open(struct net_device *netdev) return -ENOMEM; }

+ urb->transfer_dma = buf_dma; + /* fill, anchor, and submit rx urb */ usb_fill_bulk_urb(urb, dev->udev, @@ -781,10 +786,17 @@ static int gs_can_open(struct net_device *netdev) "usb_submit failed (err=%d)\n", rc);

usb_unanchor_urb(urb); + usb_free_coherent(dev->udev, + sizeof(struct gs_host_frame), + buf, + buf_dma); usb_free_urb(urb); break; }

+ dev->rxbuf[i] = buf; + dev->rxbuf_dma[i] = buf_dma; + /* Drop reference, * USB core will take care of freeing it */ @@ -842,13 +854,20 @@ static int gs_can_close(struct net_device *netdev) int rc; struct gs_can *dev = netdev_priv(netdev); struct gs_usb *parent = dev->parent; + unsigned int i;

netif_stop_queue(netdev);

/* Stop polling */ parent->active_channels--; - if (!parent->active_channels) + if (!parent->active_channels) { usb_kill_anchored_urbs(&parent->rx_submitted); + for (i = 0; i < GS_MAX_RX_URBS; i++) + usb_free_coherent(dev->udev, + sizeof(struct gs_host_frame), + dev->rxbuf[i], + dev->rxbuf_dma[i]); + }

/* Stop sending URBs */ usb_kill_anchored_urbs(&dev->tx_submitted);