Re: [PATCH v5 02/12] blk-mq: fix direct issue

Ming Lei
2017-06-07T02:50:50Z

On Tue, Jun 06, 2017 at 04:02:52PM +0000, Bart Van Assche wrote:
> On Tue, 2017-06-06 at 23:22 +0800, Ming Lei wrote:
> > If queue is stopped, we shouldn't dispatch request into driver and
> > hardware, unfortunately the check is removed in bd166ef183c2(blk-mq-sched:
> > add framework for MQ capable IO schedulers).
> >
> > This patch fixes the issue by moving the check back into
> > __blk_mq_try_issue_directly().
> >
> > This patch fixes request use-after-free[1][2] during canceling requets
> > of NVMe in nvme_dev_disable(), which can be triggered easily during
> > NVMe reset & remove test.
>
> Although I'm not convinced that this patch fixes [2], the patch itself looks

The .q_usage_counter will be leaked once request is double free.

Thanks,
Ming