From dcb7cd97f133f7cfbd181149a1e60215a869f895 Mon Sep 17 00:00:00 2001
From: Mark Huang <mlhuang@cs.princeton.edu>
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 <mlhuang@cs.princeton.edu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/bridge/netfilter/ebt_ulog.c | 3 +++
net/ipv4/netfilter/ipt_ULOG.c | 5 +++++
net/netfilter/nfnetlink_log.c | 3 +++
3 files changed, 11 insertions(+)
(limited to 'net')
diff --git a/net/bridge/netfilter/ebt_ulog.c b/net/bridge/netfilter/ebt_ulog.c
index 02693a2..9f950db 100644
--- a/net/bridge/netfilter/ebt_ulog.c
+++ b/net/bridge/netfilter/ebt_ulog.c
@@ -74,6 +74,9 @@ static void ulog_send(unsigned int nlgroup)
if (timer_pending(&ub->timer))
del_timer(&ub->timer);
+ if (!ub->skb)
+ return;
+
/* last nlmsg needs NLMSG_DONE */
if (ub->qlen > 1)
ub->lastnlh->nlmsg_type = NLMSG_DONE;
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
index d7dd7fe..d46fd67 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;
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 61cdda4..b59d3b2 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -366,6 +366,9 @@ __nfulnl_send(struct nfulnl_instance *inst)
if (timer_pending(&inst->timer))
del_timer(&inst->timer);
+ if (!inst->skb)
+ return 0;
+
if (inst->qlen > 1)
inst->lastnlh->nlmsg_type = NLMSG_DONE;
--
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