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

[Ming Lei <ming.lei@redhat.com>]

On Mon, Apr 14, 2025 at 01:44:47PM -0600, Uday Shankar wrote:
> 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;

You are right.

I just verified that all tests can pass after reverting this patch.


Thanks,
Ming