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
void __might_sleep(const char *file, int line, int preempt_offset)
{
	/*
	 * Blocking primitives will set (and therefore destroy) current->state,
	 * since we will exit with TASK_RUNNING make sure we enter with it,
	 * otherwise we will destroy state.
	 */
	WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
			"do not call blocking ops when !TASK_RUNNING; "
			"state=%lx set at [<%p>] %pS\n",
			current->state,
			(void *)current->task_state_change,
			(void *)current->task_state_change);

	___might_sleep(file, line, preempt_offset);
}

void __might_sleep(const char *file, int line, int preempt_offset)
{
	/*
	 * Blocking primitives will set (and therefore destroy) current->state,
	 * since we will exit with TASK_RUNNING make sure we enter with it,
	 * otherwise we will destroy state.
	 */
	WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
			"do not call blocking ops when !TASK_RUNNING; "
			"state=%lx set at [<%p>] %pS\n",
			current->state,
			(void *)current->task_state_change,
			(void *)current->task_state_change);

	___might_sleep(file, line, preempt_offset);
}
