Description of problem:

The sctp module tries to create an IPv6 socket when loading at sctp_ctl_sock_init() and if ipv6 module is disabled, the call returns an error failing to load the sctp module.

Version-Release number of selected component (if applicable):
2.6.18-238.el5

How reproducible:
Always

Steps to Reproduce:
1. load ipv6 module passing disable=1
2. try to load sctp module
  
The following upstream patch fixes the issue:

commit fb13d9f9e450bceafd88ac8a98f7a98e8096a5fe
Author: Brian Haley <brian.haley>
Date:   Wed Mar 4 03:20:26 2009 -0800

    SCTP: change sctp_ctl_sock_init() to try IPv4 if IPv6 fails
    
    Change sctp_ctl_sock_init() to try IPv4 if IPv6 socket registration
    fails.  Required if the IPv6 module is loaded with "disable=1", else
    SCTP will fail to load.
    
    Signed-off-by: Brian Haley <brian.haley>
    Signed-off-by: Vlad Yasevich <vladislav.yasevich>
    Signed-off-by: David S. Miller <davem>

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 4e66384..c4986d0 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -661,15 +661,19 @@ static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
 static int sctp_ctl_sock_init(void)
 {
 	int err;
-	sa_family_t family;
+	sa_family_t family = PF_INET;
 
 	if (sctp_get_pf_specific(PF_INET6))
 		family = PF_INET6;
-	else
-		family = PF_INET;
 
 	err = sock_create_kern(family, SOCK_SEQPACKET, IPPROTO_SCTP,
 			       &sctp_ctl_socket);
+
+	/* If IPv6 socket could not be created, try the IPv4 socket */
+	if (err < 0 && family == PF_INET6)
+		err = sock_create_kern(AF_INET, SOCK_SEQPACKET,
+				       IPPROTO_SCTP, &sctp_ctl_socket);
+
 	if (err < 0) {
 		printk(KERN_ERR
 		       "SCTP: Failed to create the SCTP control socket.\n");