On Thu, Dec 25, 2014 at 01:56:44AM +0200, Ahmed S. Darwish wrote:

From: Ahmed S. Darwish <redacted>

Flooding the Kvaser CAN to USB dongle with multiple reads and
writes in high frequency caused seemingly-random panics in the
kernel.

On further inspection, it seems the driver erroneously freed the
to-be-transmitted packet upon getting tight on URBs and returning
NETDEV_TX_BUSY, leading to invalid memory writes and double frees
at a later point in time.

Note:

Finding no more URBs/transmit-contexts and returning NETDEV_TX_BUSY
is a driver bug in and out of itself: it means that our start/stop
queue flow control is broken.

This patch only fixes the (buggy) error handling code; the root
cause shall be fixed in a later commit.

Signed-off-by: Ahmed S. Darwish <redacted>
---
 drivers/net/can/usb/kvaser_usb.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

 (Marc, Greg, I believe this should also be added to -stable?)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>