1 files changed, 14 insertions, 3 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index ad8eae5bb801..e887b55f1f29 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -896,10 +896,13 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode)
                 mutex_unlock(&cgroup_mutex);
 
                 /*
-                 * Drop the active superblock reference that we took when we
-                 * created the cgroup
+                 * We want to drop the active superblock reference from the
+                 * cgroup creation after all the dentry refs are gone -
+                 * kill_sb gets mighty unhappy otherwise.  Mark
+                 * dentry->d_fsdata with cgroup_diput() to tell
+                 * cgroup_d_release() to call deactivate_super().
                  */
-                deactivate_super(cgrp->root->sb);
+                dentry->d_fsdata = cgroup_diput;
 
                 /*
                  * if we're getting rid of the cgroup, refcount should ensure
@@ -925,6 +928,13 @@ static int cgroup_delete(const struct dentry *d)
         return 1;
 }
 
+static void cgroup_d_release(struct dentry *dentry)
+{
+        /* did cgroup_diput() tell me to deactivate super? */
+        if (dentry->d_fsdata == cgroup_diput)
+                deactivate_super(dentry->d_sb);
+}
+
 static void remove_dir(struct dentry *d)
 {
         struct dentry *parent = dget(d->d_parent);
@@ -1532,6 +1542,7 @@ static int cgroup_get_rootdir(struct super_block *sb)
         static const struct dentry_operations cgroup_dops = {
                 .d_iput = cgroup_diput,
                 .d_delete = cgroup_delete,
+                .d_release = cgroup_d_release,
         };
 
         struct inode *inode =