[PATCH v2] can: mcba_usb: Fix memory leak when cancelling urb

[Bui Quang Minh]

In mcba_usb_read_bulk_callback(), when we don't resubmit or fails to
resubmit the urb, we need to deallocate the transfer buffer that is
allocated in mcba_usb_start().

Reported-by: syzbot+57281c762a3922e14...@syzkaller.appspotmail.com
Signed-off-by: Bui Quang Minh <minhquangbu...@gmail.com>
---
v1: add memory leak fix when not resubmitting urb
v2: add memory leak fix when failing to resubmit urb

 drivers/net/can/usb/mcba_usb.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c
index df54eb7d4b36..30236e640116 100644
--- a/drivers/net/can/usb/mcba_usb.c
+++ b/drivers/net/can/usb/mcba_usb.c
@@ -584,6 +584,8 @@ static void mcba_usb_read_bulk_callback(struct urb *urb)
        case -EPIPE:
        case -EPROTO:
        case -ESHUTDOWN:
+               usb_free_coherent(urb->dev, urb->transfer_buffer_length,
+                                 urb->transfer_buffer, urb->transfer_dma);
                return;
 
        default:
@@ -615,11 +617,14 @@ static void mcba_usb_read_bulk_callback(struct urb *urb)
 
        retval = usb_submit_urb(urb, GFP_ATOMIC);
 
-       if (retval == -ENODEV)
-               netif_device_detach(netdev);
-       else if (retval)
+       if (retval < 0) {
                netdev_err(netdev, "failed resubmitting read bulk urb: %d\n",
                           retval);
+               usb_free_coherent(urb->dev, urb->transfer_buffer_length,
+                                 urb->transfer_buffer, urb->transfer_dma);
+               if (retval == -ENODEV)
+                       netif_device_detach(netdev);
+       }
 }
 
 /* Start USB device */
-- 
2.17.1