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>

1 files changed, 10 insertions, 9 deletions

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index a697591d0e2..0b884d3e192 100644
--- 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 */