[DLM] Fix kref_put oops

This patch fixes the recounting on the lockspace kobject. Previously the lockspace was freed while userspace could have had a
reference to one of its sysfs files, causing an oops in kref_put.

Now the lockspace kfree is moved into the kobject release() function

Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 109333c8ecb9..499ee1156365 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -143,6 +143,12 @@ static ssize_t dlm_attr_store(struct kobject *kobj, struct attribute *attr,
         return a->store ? a->store(ls, buf, len) : len;
 }
 
+static void lockspace_kobj_release(struct kobject *k)
+{
+        struct dlm_ls *ls  = container_of(k, struct dlm_ls, ls_kobj);
+        kfree(ls);
+}
+
 static struct sysfs_ops dlm_attr_ops = {
         .show  = dlm_attr_show,
         .store = dlm_attr_store,
@@ -151,6 +157,7 @@ static struct sysfs_ops dlm_attr_ops = {
 static struct kobj_type dlm_ktype = {
         .default_attrs = dlm_attrs,
         .sysfs_ops     = &dlm_attr_ops,
+        .release       = lockspace_kobj_release,
 };
 
 static struct kset dlm_kset = {
@@ -678,7 +685,7 @@ static int release_lockspace(struct dlm_ls *ls, int force)
         dlm_clear_members_gone(ls);
         kfree(ls->ls_node_array);
         kobject_unregister(&ls->ls_kobj);
-        kfree(ls);
+        /* The ls structure will be freed when the kobject is done with */
 
         mutex_lock(&ls_lock);
         ls_count--;