1 files changed, 20 insertions, 5 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 2810e562a991..e51f0eabfef2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5461,11 +5461,12 @@ static void register_sched_domain_sysctl(void)
         struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
         char buf[32];
 
+        WARN_ON(sd_ctl_dir[0].child);
+        sd_ctl_dir[0].child = entry;
+
         if (entry == NULL)
                 return;
 
-        sd_ctl_dir[0].child = entry;
-
         for_each_online_cpu(i) {
                 snprintf(buf, 32, "cpu%d", i);
                 entry->procname = kstrdup(buf, GFP_KERNEL);
@@ -5473,14 +5474,19 @@ static void register_sched_domain_sysctl(void)
                 entry->child = sd_alloc_ctl_cpu_table(i);
                 entry++;
         }
+
+        WARN_ON(sd_sysctl_header);
         sd_sysctl_header = register_sysctl_table(sd_ctl_root);
 }
 
+/* may be called multiple times per register */
 static void unregister_sched_domain_sysctl(void)
 {
-        unregister_sysctl_table(sd_sysctl_header);
+        if (sd_sysctl_header)
+                unregister_sysctl_table(sd_sysctl_header);
         sd_sysctl_header = NULL;
-        sd_free_ctl_entry(&sd_ctl_dir[0].child);
+        if (sd_ctl_dir[0].child)
+                sd_free_ctl_entry(&sd_ctl_dir[0].child);
 }
 #else
 static void register_sched_domain_sysctl(void)
@@ -6424,13 +6430,17 @@ static cpumask_t fallback_doms;
  */
 static int arch_init_sched_domains(const cpumask_t *cpu_map)
 {
+        int err;
+
         ndoms_cur = 1;
         doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
         if (!doms_cur)
                 doms_cur = &fallback_doms;
         cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
+        err = build_sched_domains(doms_cur);
         register_sched_domain_sysctl();
-        return build_sched_domains(doms_cur);
+
+        return err;
 }
 
 static void arch_destroy_sched_domains(const cpumask_t *cpu_map)
@@ -6479,6 +6489,9 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new)
 {
         int i, j;
 
+        /* always unregister in case we don't destroy any domains */
+        unregister_sched_domain_sysctl();
+
         if (doms_new == NULL) {
                 ndoms_new = 1;
                 doms_new = &fallback_doms;
@@ -6514,6 +6527,8 @@ match2:
                 kfree(doms_cur);
         doms_cur = doms_new;
         ndoms_cur = ndoms_new;
+
+        register_sched_domain_sysctl();
 }
 
 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)