In the Linux kernel, the following vulnerability has been resolved:

net: sxgbe: fix potential NULL dereference in sxgbe_rx()

Currently, when skb is null, the driver prints an error and then
dereferences skb on the next line.

To fix this, let's add a 'break' after the error message to switch
to sxgbe_rx_refill(), which is similar to the approach taken by the
other drivers in this particular case, e.g. calxeda with xgmac_rx().

Found during a code review.