cgfs: fix invalid free()

And let's be on the safe side by NULLing free()ed variables.

Signed-off-by: Christian Brauner <christian.brauner@canonical.com>

diff --git a/src/lxc/cgfs.c b/src/lxc/cgfs.c
index 1accdde0123dadab3e7c4f127d98ee2597894260..bdbacf4785d66bb08bd131a600e7210598b61cab 100644 (file)
--- a/src/lxc/cgfs.c
+++ b/src/lxc/cgfs.c
@@ -615,10 +615,10 @@ static struct cgroup_meta_data *lxc_cgroup_put_meta(struct cgroup_meta_data *met
        if (--meta_data->ref > 0)
                return meta_data;
        lxc_free_array((void **)meta_data->mount_points, (lxc_free_fn)lxc_cgroup_mount_point_free);
-       if (meta_data->hierarchies) {
+       if (meta_data->hierarchies)
                for (i = 0; i <= meta_data->maximum_hierarchy; i++)
-                       lxc_cgroup_hierarchy_free(meta_data->hierarchies[i]);
-       }
+                       if (meta_data->hierarchies[i])
+                               lxc_cgroup_hierarchy_free(meta_data->hierarchies[i]);
        free(meta_data->hierarchies);
        free(meta_data);
        return NULL;
@@ -1761,9 +1761,16 @@ static void lxc_cgroup_hierarchy_free(struct cgroup_hierarchy *h)
 {
        if (!h)
                return;
-       lxc_free_array((void **)h->subsystems, free);
-       free(h->all_mount_points);
+       if (h->subsystems) {
+               lxc_free_array((void **)h->subsystems, free);
+               h->subsystems = NULL;
+       }
+       if (h->all_mount_points) {
+               free(h->all_mount_points);
+               h->all_mount_points = NULL;
+       }
        free(h);
+       h = NULL;
 }
 
 static bool is_valid_cgroup(const char *name)