linux-kernel - Re: [PATCH v2] nbd: Don't use workqueue to handle recv work

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Message-ID: <Ycycda8w/zHWGw9c@infradead.org>
Date:   Wed, 29 Dec 2021 09:35:49 -0800
From:   Christoph Hellwig <hch@...radead.org>
To:     Xie Yongji <xieyongji@...edance.com>
Cc:     josef@...icpanda.com, axboe@...nel.dk, bvanassche@....org,
        linux-block@...r.kernel.org, nbd@...er.debian.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] nbd: Don't use workqueue to handle recv work

On Mon, Dec 27, 2021 at 05:12:41PM +0800, Xie Yongji wrote:
> The rescuer thread might take over the works queued on
> the workqueue when the worker thread creation timed out.
> If this happens, we have no chance to create multiple
> recv threads which causes I/O hung on this nbd device.

If a workqueue is used there aren't really 'receive threads'.
What is the deadlock here?