netdev - Re: kernel panic TPROXY , vanilla 4.7.1

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Date:	Wed, 17 Aug 2016 19:44:22 +0300
From:	Denys Fedoryshchenko <nuclearcat@...learcat.com>
To:	Eric Dumazet <eric.dumazet@...il.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 2016-08-17 19:04, Eric Dumazet wrote:
> 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
Yes, everything fine after patch!
Thanks a lot