Re: [PATCH] SCSI: Fix hard lockup in scsi_remove_target()

Christoph Hellwig
2015-10-02T12:49:24Z

> - list_for_each_entry(starget, &shost->__targets, siblings) {
> + list_for_each_entry_safe(starget, tmp, &shost->__targets, siblings) {
> if (starget->state == STARGET_DEL)
> continue;
> if (starget->dev.parent == dev || &starget->dev == dev) {
> /* assuming new targets arrive at the end */

Now that the last variable is gone this comments isn't needed.

> kref_get(&starget->reap_ref);
> spin_unlock_irqrestore(shost->host_lock, flags);
> - if (last)
> - scsi_target_reap(last);
> - last = starget;
> +
> __scsi_remove_target(starget);
> + list_move_tail(&starget->siblings, &reap_list);
> spin_lock_irqsave(shost->host_lock, flags);
> }

What makes the list_move save after dropping host_lock? I think this
needs to be changed to not drop the host_lock and change
__scsi_remove_target to expect host_lock held to be safe.