Re: [PATCH 1/9] ublk: don't try to stop disk if ->ub_disk is NULL

[Uday Shankar <ushankar@xxxxxxxxxxxxxxx>]

On Mon, Apr 14, 2025 at 07:25:42PM +0800, Ming Lei wrote:
> In ublk_stop_dev(), if ublk device state becomes UBLK_S_DEV_DEAD, we
> will return immediately. This way is correct, but not enough, because
> ublk device may transition to other state, such UBLK_S_DEV_QUIECED,
> when it may have been stopped already. Then kernel panic is triggered.

How can this happen? If a device is stopped, it is in the
UBLK_S_DEV_DEAD state. Won't that make us fall out of this check in
ublk_nosrv_work, so we wont transition to UBLK_S_DEV_QUIESCED or other
nosrv states?

	mutex_lock(&ub->mutex);
	if (ub->dev_info.state != UBLK_S_DEV_LIVE)
		goto unlock;