[bug report] nvme-tcp poll queue causes busy loop and 100% CPU in nvme_tcp_poll() on the latest linux-block/for-next

[Yi Zhang]

On Wed, Jan 21, 2026 at 4:53 PM Ming Lei <ming.lei at redhat.com> wrote:
>
> On Wed, Jan 21, 2026 at 10:50:00AM +0800, Yi Zhang wrote:
> > Hi
> >
> > This issue was observed on the latest linux-block/for-next during CKI
> > test, where enabling the poll queues leads to a tight busy polling
> > loop and 100% CPU usage during "nvme connect".
> > It seems was introduced from v6.19-rc1 and cannot reproduced on v6.18.
> > I will try to bisect it.
>
> It may be related with f22ecf9c14c1 ("blk-mq: delete task running check
> in blk_hctx_poll()").

This commit merged to v6.19-rc1, I will revert it and retest.

>
> I guess it only happens when `nvme connect` takes a bit long time, not sure if
> it can be reproduced 100%.

Correct, it's 100% reproduced.

>
>
> Thanks,
> Ming
>


-- 
Best Regards,
  Yi Zhang