1 files changed, 13 insertions, 5 deletions

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 842c254396db..b08d20c66c2e 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -164,8 +164,8 @@ static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
         struct dev_exception_item *ex, *tmp;
 
         list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
-                list_del(&ex->list);
-                kfree(ex);
+                list_del_rcu(&ex->list);
+                kfree_rcu(ex, rcu);
         }
 }
 
@@ -298,7 +298,7 @@ static int may_access(struct dev_cgroup *dev_cgroup,
         struct dev_exception_item *ex;
         bool match = false;
 
-        list_for_each_entry(ex, &dev_cgroup->exceptions, list) {
+        list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) {
                 if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK))
                         continue;
                 if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR))
@@ -352,6 +352,8 @@ static int parent_has_perm(struct dev_cgroup *childcg,
  */
 static inline int may_allow_all(struct dev_cgroup *parent)
 {
+        if (!parent)
+                return 1;
         return parent->behavior == DEVCG_DEFAULT_ALLOW;
 }
 
@@ -376,11 +378,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
         int count, rc;
         struct dev_exception_item ex;
         struct cgroup *p = devcgroup->css.cgroup;
-        struct dev_cgroup *parent = cgroup_to_devcgroup(p->parent);
+        struct dev_cgroup *parent = NULL;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
+        if (p->parent)
+                parent = cgroup_to_devcgroup(p->parent);
+
         memset(&ex, 0, sizeof(ex));
         b = buffer;
 
@@ -391,11 +396,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
                         if (!may_allow_all(parent))
                                 return -EPERM;
                         dev_exception_clean(devcgroup);
+                        devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
+                        if (!parent)
+                                break;
+
                         rc = dev_exceptions_copy(&devcgroup->exceptions,
                                                  &parent->exceptions);
                         if (rc)
                                 return rc;
-                        devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
                         break;
                 case DEVCG_DENY:
                         dev_exception_clean(devcgroup);