kernel/user.c: fix a memory leak when freeing up non-init usernamespaces users
Dhaval Giani [Tue, 10 Mar 2009 19:55:56 +0000 (12:55 -0700)]
We were returning early in the sysfs directory cleanup function if the
user belonged to a non init usernamespace.  Due to this a lot of the
cleanup was not done and we were left with a leak.  Fix the leak.

Reported-by: Serge Hallyn <serue@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/user.c

index 6a9b696..fbb300e 100644 (file)
@@ -286,14 +286,12 @@ int __init uids_sysfs_init(void)
 /* work function to remove sysfs directory for a user and free up
  * corresponding structures.
  */
-static void remove_user_sysfs_dir(struct work_struct *w)
+static void cleanup_user_struct(struct work_struct *w)
 {
        struct user_struct *up = container_of(w, struct user_struct, work);
        unsigned long flags;
        int remove_user = 0;
 
-       if (up->user_ns != &init_user_ns)
-               return;
        /* Make uid_hash_remove() + sysfs_remove_file() + kobject_del()
         * atomic.
         */
@@ -312,9 +310,11 @@ static void remove_user_sysfs_dir(struct work_struct *w)
        if (!remove_user)
                goto done;
 
-       kobject_uevent(&up->kobj, KOBJ_REMOVE);
-       kobject_del(&up->kobj);
-       kobject_put(&up->kobj);
+       if (up->user_ns == &init_user_ns) {
+               kobject_uevent(&up->kobj, KOBJ_REMOVE);
+               kobject_del(&up->kobj);
+               kobject_put(&up->kobj);
+       }
 
        sched_destroy_user(up);
        key_put(up->uid_keyring);
@@ -335,7 +335,7 @@ static void free_user(struct user_struct *up, unsigned long flags)
        atomic_inc(&up->__count);
        spin_unlock_irqrestore(&uidhash_lock, flags);
 
-       INIT_WORK(&up->work, remove_user_sysfs_dir);
+       INIT_WORK(&up->work, cleanup_user_struct);
        schedule_work(&up->work);
 }