Merge branch 'stacking-fixes' (vfs stacking fixes from Jann)

Merge filesystem stacking fixes from Jann Horn.

* emailed patches from Jann Horn <jannh@google.com>:
  sched: panic on corrupted stack end
  ecryptfs: forbid opening files without mmap handler
  proc: prevent stacking filesystems on top
static void proc_kill_sb(struct super_block *sb)
{
	struct pid_namespace *ns;

	ns = (struct pid_namespace *)sb->s_fs_info;
	if (ns->proc_self)
		dput(ns->proc_self);
	if (ns->proc_thread_self)
		dput(ns->proc_thread_self);
	kill_anon_super(sb);
	put_pid_ns(ns);
}

static void proc_kill_sb(struct super_block *sb)
{
	struct pid_namespace *ns;

	ns = (struct pid_namespace *)sb->s_fs_info;
	if (ns->proc_self)
		dput(ns->proc_self);
	if (ns->proc_thread_self)
		dput(ns->proc_thread_self);
	kill_anon_super(sb);
	put_pid_ns(ns);
}
