linux-kernel - Problem with "tcp: bind() fix when many ports are bound" commit

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Date:	Wed, 28 Apr 2010 14:33:45 +0200
From:	Grzegorz Chwesewicz <grzegorz.chwesewicz@...is.net.pl>
To:	linux-kernel@...r.kernel.org
Subject: Problem with "tcp: bind() fix when many ports are bound" commit

	Hi, I have a problem with binding to port with the latest git kernel
(my HEAD is at 1600f9def09de07c5dbeb539e978fa73880690dd). Please CC to
me as I'm not subscribed to the list.

Example with buggy kernel:

ensima-hp ~ # /etc/init.d/apache2 start
 * Starting apache2 ...
(98)Address already in use: make_sock: could not bind to address
127.0.0.1:80
no listening sockets available, shutting down
Unable to open logs

As you can see nothing is listening on port 80, but there are old
connections to port 80 with CLOSE_WAIT and FIN_WAIT2 state.

ensima-hp ~ # netstat -pan --inet|grep 80
netstat: no support for `AF INET (sctp)' on this system.
tcp        0      0 127.0.0.1:631           0.0.0.0:*
LISTEN      4806/cupsd
tcp        1      0 127.0.0.1:54040         127.0.0.1:80
CLOSE_WAIT  5814/konquerorHk573
tcp        0      0 127.0.0.1:80            127.0.0.1:54042
FIN_WAIT2   -
tcp        0      0 127.0.0.1:80            127.0.0.1:54040
FIN_WAIT2   -
tcp        1      0 127.0.0.1:54042         127.0.0.1:80
CLOSE_WAIT  6175/konquerordx573

So I can't start apache as long as these connections are not fully
closed, after that apache starts without problems.

ensima-hp ~ # netstat -pan --inet|grep 80
netstat: no support for `AF INET (sctp)' on this system.
tcp        0      0 127.0.0.1:631           0.0.0.0:*
LISTEN      4806/cupsd

ensima-hp ~ # /etc/init.d/apache2 start
 * Starting apache2 ...		[OK]

Problem occured between 2.6.34-rc4 and latest git, bisect shows that the
problem is caused by:

commit fda48a0d7a8412cedacda46a9c0bf8ef9cd13559
Author: Eric Dumazet <eric.dumazet@...il.com>
Date:   Wed Apr 21 09:26:15 2010 +0000

tcp: bind() fix when many ports are bound

Reverting this commit from current HEAD, resolving conflict in
'net/ipv6/inet6_connection_sock.c' file, and compiling new kernel solves
the problem.

'net/ipv6/inet6_connection_sock.c' before resolving conflict:

 41         sk_for_each_bound(sk2, node, &tb->owners) {
 42                 if (sk != sk2 &&
 43                     (!sk->sk_bound_dev_if ||
 44                      !sk2->sk_bound_dev_if ||
 45 <<<<<<< HEAD
 46                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
 47                         if ((!sk->sk_reuse || !sk2->sk_reuse ||
 48                              sk2->sk_state == TCP_LISTEN) &&
 49                              ipv6_rcv_saddr_equal(sk, sk2))
 50                                 break;
 51                         else if (sk->sk_reuse && sk2->sk_reuse &&
 52                                 !ipv6_addr_any(inet6_rcv_saddr(sk)) &&
 53                                 ipv6_rcv_saddr_equal(sk, sk2))
 54                                 break;
 55                 }
 56 =======
 57                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if) &&
 58                     (!sk->sk_reuse || !sk2->sk_reuse ||
 59                      sk2->sk_state == TCP_LISTEN) &&
 60                      ipv6_rcv_saddr_equal(sk, sk2))
 61                         break;
 62 >>>>>>> fda48a0... tcp: bind() fix when many ports are bound
 63         }
 64
 65         return node != NULL;



 66 }

'net/ipv6/inet6_connection_sock.c' after resolving conflict:

 41         sk_for_each_bound(sk2, node, &tb->owners) {
 42                 if (sk != sk2 &&
 43                     (!sk->sk_bound_dev_if ||
 44                      !sk2->sk_bound_dev_if ||
 45                      sk->sk_bound_dev_if == sk2->sk_bound_dev_if) &&
 46                     (!sk->sk_reuse || !sk2->sk_reuse ||
 47                      sk2->sk_state == TCP_LISTEN) &&
 48                      ipv6_rcv_saddr_equal(sk, sk2))
 49                         break;
 50         }



 51
 52         return node != NULL;
 53 }

-- 
Greetings
Grzegorz Chwesewicz
mailto:grzegorz.chwesewicz@...is.net.pl
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