Hello,
On Mon, Oct 23, 2017 at 09:34:11AM +0800, Li Bin wrote:
>
>
> on 2017/10/21 23:35, Tejun Heo wrote:
> > On Fri, Oct 20, 2017 at 02:57:18PM +0800, tanxiaofei wrote:
> >> Hi Tejun,
> >>
> >> Any comments about this?
> >
> > I think you're confused, or at least can't understand what you're
> > trying to say. Can you create a rero?
> >
>
> Hi Tejun,
> The case is as following:
>
> worker_thread()
> |-spin_lock_irq()
> |-process_one_work()
> |-worker->current_pwq = pwq
> |-spin_unlock_irq()
> |-worker->current_func(work)
> |-spin_lock_irq()
> |-worker->current_pwq = NULL
> |-spin_unlock_irq()
>
> //interrupt here
>
> |-irq_handler
>
> |-__queue_work()
>
> //assuming that the wq is draining
>
> |-if (unlikely(wq->flags & __WQ_DRAINING)
> &&WARN_ON_ONCE(!is_chained_work(wq)))
>
> |-is_chained_work(wq)
>
> |-current_wq_worker() // Here, 'current' is the interrupted worker!
>
> |-current->current_pwq is NULL here!
> |-schedule()
>
> And I think the following patch can solve the bug, right?
>
> diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
> index 8635417..650680c 100644
> --- a/kernel/workqueue_internal.h
> +++ b/kernel/workqueue_internal.h
> @@ -59,7 +59,7 @@ struct worker {
> */
> static inline struct worker *current_wq_worker(void)
> {
> - if (current->flags & PF_WQ_WORKER)
> + if (!in_irq() && (current->flags & PF_WQ_WORKER))
> return kthread_data(current);
> return NULL;
> }
Yeah, that makes sense to me. Can you please resend the patch with
patch description and SOB?
Thanks.
--
tejun
