Fixed race condition at ip_vs.ko module init.

Lists were initialized after the module was registered.  Multiple ipvsadm
processes at module load triggered a race condition that resulted in a null
pointer dereference in do_ip_vs_get_ctl(). As a result, __ip_vs_mutex
was left locked preventing all further ipvsadm commands.

Signed-off-by: Eduardo J. Blanco <ejblanco@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index a697591d0e230e19311650123e9a6592e4639a46..0b884d3e192fafa92f2dc68c97c8bb6f782a33c8 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -3400,6 +3400,16 @@ int __init ip_vs_control_init(void)
 
        EnterFunction(2);
 
+       /* Initialize ip_vs_svc_table, ip_vs_svc_fwm_table, ip_vs_rtable */
+       for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++)  {
+               INIT_LIST_HEAD(&ip_vs_svc_table[idx]);
+               INIT_LIST_HEAD(&ip_vs_svc_fwm_table[idx]);
+       }
+       for(idx = 0; idx < IP_VS_RTAB_SIZE; idx++)  {
+               INIT_LIST_HEAD(&ip_vs_rtable[idx]);
+       }
+       smp_wmb();
+
        ret = nf_register_sockopt(&ip_vs_sockopts);
        if (ret) {
                pr_err("cannot register sockopt.\n");
@@ -3418,15 +3428,6 @@ int __init ip_vs_control_init(void)
 
        sysctl_header = register_sysctl_paths(net_vs_ctl_path, vs_vars);
 
-       /* Initialize ip_vs_svc_table, ip_vs_svc_fwm_table, ip_vs_rtable */
-       for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++)  {
-               INIT_LIST_HEAD(&ip_vs_svc_table[idx]);
-               INIT_LIST_HEAD(&ip_vs_svc_fwm_table[idx]);
-       }
-       for(idx = 0; idx < IP_VS_RTAB_SIZE; idx++)  {
-               INIT_LIST_HEAD(&ip_vs_rtable[idx]);
-       }
-
        ip_vs_new_estimator(&ip_vs_stats);
 
        /* Hook the defense timer */