Package: kernel-tree-2.6.8 Version: 2.6.8-16 I wasn't sure which package to file this under so I opted for the kernel-tree package.
Details and patch are available on the netfilter list. This is a pretty nasty bug. https://lists.netfilter.org/pipermail/netfilter-devel/2005-July/020513.html As far as I can tell this is still affecting the 2.6.8 images provided in sarge, specifically I am using Debian 3.1 (sarge) with all security updates applied and kernel 2.6.8-2-686-smp . Text from that link: --QUOTED TEXT-- Patrick McHardy kaber at trash.net Thu Jul 21 09:44:44 CEST 2005 Previous message: ip_queue freeze with 2.6.9 RHEL4 Next message: [PATCH] reduce netfilte sk_buff enlargement Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Eric Leblond wrote: > I've got one rule only : > iptables -A INPUT -p tcp --dport 22 --syn -j ACCEPT > > It freezes just after I send the NF_ACCEPT decision. This looks like a problem we've already fixed in current kernels. Please try this patch. -------------- next part -------------- [NETFILTER]: Fix deadlock with ip_queue and tcp local input path. When we have ip_queue being used from LOCAL_IN, then we end up with a situation where the verdicts coming back from userspace traverse the TCP input path from syscall context. While this seems to work most of the time, there's an ugly deadlock: syscall context is interrupted by the timer interrupt. When the timer interrupt leaves, the timer softirq get's scheduled and calls tcp_delack_timer() and alike. They themselves do bh_lock_sock(sk), which is already held from somewhere else -> boom. I've now tested the suggested solution by Patrick McHardy and Herbert Xu to simply use local_bh_{en,dis}able(). Signed-off-by: Harald Welte <laforge at netfilter.org> Signed-off-by: David S. Miller <davem at davemloft.net> --- commit 9bb7bc942d3da606f184ac6a4dfc7e4d470c831b tree dc310200df5988d4c71c346baad6a923a4bdeb9d parent 5e485b7975472ba4a408523deb6541e70c451842 author Harald Welte <laforge at netfilter.org> Mon, 30 May 2005 15:35:26 -0700 committer David S. Miller <davem at davemloft.net> Mon, 30 May 2005 15:35:26 -0700 net/ipv4/netfilter/ip_queue.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -3,6 +3,7 @@ * communicating with userspace via netlink. * * (C) 2000-2002 James Morris <jmorris at intercode.com.au> + * (C) 2003-2005 Netfilter Core Team <coreteam at netfilter.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as @@ -17,6 +18,7 @@ * 2005-01-10: Added /proc counter for dropped packets; fixed so * packets aren't delivered to user space if they're going * to be dropped. + * 2005-05-26: local_bh_{disable,enable} around nf_reinject (Harald Welte) * */ #include <linux/module.h> @@ -71,7 +73,15 @@ static DECLARE_MUTEX(ipqnl_sem); static void ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict) { + /* TCP input path (and probably other bits) assume to be called + * from softirq context, not from syscall, like ipq_issue_verdict is + * called. TCP input path deadlocks with locks taken from timer + * softirq, e.g. We therefore emulate this by local_bh_disable() */ + + local_bh_disable(); nf_reinject(entry->skb, entry->info, verdict); + local_bh_enable(); + kfree(entry); } --END QUOTED TEXT--
