cgroups: avoid accessing uninitialized data in failure path

[linux-2.6-omap-h63xx.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 358e77564e6f8b0b4c3964a36da48cc3051d6e73..2606d0fb4e54e8f120618328c7b72c01634dc35d 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -702,7 +702,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
         * any child cgroups exist. This is theoretically supportable
         * but involves complex error handling, so it's being left until
         * later */
-       if (!list_empty(&cgrp->children))
+       if (root->number_of_cgroups > 1)
                return -EBUSY;
 
        /* Process each subsystem */
@@ -1024,7 +1024,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
                if (ret == -EBUSY) {
                        mutex_unlock(&cgroup_mutex);
                        mutex_unlock(&inode->i_mutex);
-                       goto drop_new_super;
+                       goto free_cg_links;
                }
 
                /* EBUSY should be the only error here */
@@ -1073,10 +1073,11 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
 
        return simple_set_mnt(mnt, sb);
 
+ free_cg_links:
+       free_cg_links(&tmp_cg_links);
  drop_new_super:
        up_write(&sb->s_umount);
        deactivate_super(sb);
-       free_cg_links(&tmp_cg_links);
        return ret;
 }
 
@@ -2039,10 +2040,13 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
        struct cgroup *cgrp;
        struct cgroup_iter it;
        struct task_struct *tsk;
+
        /*
-        * Validate dentry by checking the superblock operations
+        * Validate dentry by checking the superblock operations,
+        * and make sure it's a directory.
         */
-       if (dentry->d_sb->s_op != &cgroup_ops)
+       if (dentry->d_sb->s_op != &cgroup_ops ||
+           !S_ISDIR(dentry->d_inode->i_mode))
                 goto err;
 
        ret = 0;
@@ -2472,10 +2476,7 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
                mutex_unlock(&cgroup_mutex);
                return -EBUSY;
        }
-
-       parent = cgrp->parent;
-       root = cgrp->root;
-       sb = root->sb;
+       mutex_unlock(&cgroup_mutex);
 
        /*
         * Call pre_destroy handlers of subsys. Notify subsystems
@@ -2483,7 +2484,14 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
         */
        cgroup_call_pre_destroy(cgrp);
 
-       if (cgroup_has_css_refs(cgrp)) {
+       mutex_lock(&cgroup_mutex);
+       parent = cgrp->parent;
+       root = cgrp->root;
+       sb = root->sb;
+
+       if (atomic_read(&cgrp->count)
+           || !list_empty(&cgrp->children)
+           || cgroup_has_css_refs(cgrp)) {
                mutex_unlock(&cgroup_mutex);
                return -EBUSY;
        }
@@ -2927,9 +2935,6 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
  again:
        root = subsys->root;
        if (root == &rootnode) {
-               printk(KERN_INFO
-                      "Not cloning cgroup for unused subsystem %s\n",
-                      subsys->name);
                mutex_unlock(&cgroup_mutex);
                return 0;
        }