netdev - Re: kernel panic TPROXY , vanilla 4.7.1

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Date:	Wed, 17 Aug 2016 09:04:31 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Denys Fedoryshchenko <nuclearcat@...learcat.com>
Cc:	Linux Kernel Network Developers <netdev@...r.kernel.org>,
	netfilter-devel@...r.kernel.org
Subject: Re: kernel panic TPROXY , vanilla 4.7.1

On Wed, 2016-08-17 at 08:42 -0700, Eric Dumazet wrote:
> On Wed, 2016-08-17 at 17:31 +0300, Denys Fedoryshchenko wrote:
> > Hi!
> > 
> > Tried to run squid on latest kernel, and hit a panic
> > Sometimes it just shows warning in dmesg (but doesnt work properly)
> > [   75.701666] IPv4: Attempt to release TCP socket in state 10 
> > ffff88102d430780
> > [   83.866974] squid (2700) used greatest stack depth: 12912 bytes left
> > [   87.506644] IPv4: Attempt to release TCP socket in state 10 
> > ffff880078a48780
> > [  114.704295] IPv4: Attempt to release TCP socket in state 10 
> > ffff881029f8ad00
> > 
> > I cannot catch yet oops/panic message, netconsole not working.
> > 
> > After triggering warning message 3 times, i am unable to run squid 
> > anymore (without reboot), and in netstat it doesnt show port running.
> > 
> > firewall is:
> > *mangle
> > -A PREROUTING -p tcp -m socket -j DIVERT
> > -A PREROUTING -p tcp -m tcp --dport 80 -i eno1 -j TPROXY --on-port 3129 
> > --on-ip 0.0.0.0 --tproxy-mark 0x1/0x1
> > -A DIVERT -j MARK --set-xmark 0x1/0xffffffff
> > -A DIVERT -j ACCEPT
> > 
> > routing
> > ip rule add fwmark 1 lookup 100
> > ip route add local default dev eno1 table 100
> > 
> > 
> > squid config is default with tproxy option
> > http_port 3129 tproxy
> > 
> 
> Hmppff... sorry for this, I will send a fix.
> 
> Thanks for the report !
> 


Could you try the following ?

Thanks !

 net/netfilter/xt_TPROXY.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
index 7f4414d26a66..663c4c3c9072 100644
--- a/net/netfilter/xt_TPROXY.c
+++ b/net/netfilter/xt_TPROXY.c
@@ -127,6 +127,8 @@ nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, void *hp,
 						    daddr, dport,
 						    in->ifindex);
 
+			if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+				sk = NULL;
 			/* NOTE: we return listeners even if bound to
 			 * 0.0.0.0, those are filtered out in
 			 * xt_socket, since xt_TPROXY needs 0 bound
@@ -195,6 +197,8 @@ nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff, void *hp,
 						   daddr, ntohs(dport),
 						   in->ifindex);
 
+			if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+				sk = NULL;
 			/* NOTE: we return listeners even if bound to
 			 * 0.0.0.0, those are filtered out in
 			 * xt_socket, since xt_TPROXY needs 0 bound