[PATCH] Fix ipt_ULOG panics on SMP kernels

[Patrick McHardy]

Mark Huang wrote:
> Fix kernel panic on various SMP machines. The culprit is a null
> ub->skb in ulog_send(). If ulog_timer() has already been scheduled on
> one CPU and is spinning on the lock, and ipt_ulog_packet() flushes the
> queue on another CPU by calling ulog_send() right before it exits,
> there will be no skbuff when ulog_timer() acquires the lock and calls
> ulog_send(). Cancelling the timer in ulog_send() doesn't help because
> it has already been scheduled and is running on the first CPU.
> 
> Similar problem exists in ebt_ulog.c and nfnetlink_log.c.

Applied, thanks Mark.