CVE-2021-47231

In the Linux kernel, the following vulnerability has been resolved: can:
mcba_usb: fix memory leak in mcba_usb Syzbot reported memory leak in
SocketCAN driver for Microchip CAN BUS Analyzer Tool. The problem was in
unfreed usb_coherent. In mcba_usb_start() 20 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 mcba_usb_start) and this flag
cannot be used with coherent buffers. Fail log: | [ 1354.053291][ T8413]
mcba_usb 1-1:0.0 can0: device disconnected | [ 1367.059384][ T8420]
kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem) So,
all allocated buffers should be freed with usb_free_coherent() explicitly
NOTE: The same pattern for allocating and freeing coherent buffers is used
in drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c