Re: Spurious witness warning when destroying spin mtx

On Sat, Nov 24, 2012 at 10:01 AM, Attilio Rao <attilio_at_freebsd.org> wrote:

> I seriously wonder why right now we don't assume the lock is unheld.
> There are likely historically reasons for that, but I would like to
> know which one are those and eventually fix them out.
> FWIK, all the other locking primitives assume the lock is already
> unheld when destroying and I think it would be good to have that for
> mutexes as well.
>
> Can you please show which lock triggers the panic you saw?
>
> Thanks,
> Attilio
>
>
It was taskqueue_free:

void
taskqueue_free(struct taskqueue *queue)
{

        TQ_LOCK(queue);
        queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
        taskqueue_terminate(queue->tq_threads, queue);
        KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
        KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
        mtx_destroy(&queue->tq_mutex);
        free(queue->tq_threads, M_TASKQUEUE);
        free(queue, M_TASKQUEUE);
}