From dcb7cd97f133f7cfbd181149a1e60215a869f895 Mon Sep 17 00:00:00 2001 From: Mark Huang Date: Sun, 13 Aug 2006 18:57:54 -0700 Subject: [NETFILTER]: ulog: fix panic on SMP kernels 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. Signed-off-by: Mark Huang Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/ipv4/netfilter/ipt_ULOG.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/ipv4/netfilter/ipt_ULOG.c') diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c index d7dd7fe7051c..d46fd677fa11 100644 --- a/net/ipv4/netfilter/ipt_ULOG.c +++ b/net/ipv4/netfilter/ipt_ULOG.c @@ -115,6 +115,11 @@ static void ulog_send(unsigned int nlgroupnum) del_timer(&ub->timer); } + if (!ub->skb) { + DEBUGP("ipt_ULOG: ulog_send: nothing to send\n"); + return; + } + /* last nlmsg needs NLMSG_DONE */ if (ub->qlen > 1) ub->lastnlh->nlmsg_type = NLMSG_DONE; -- cgit v1.2.3