On Wed, Jul 08, 2015 at 11:06:09AM +0200, Hannes Reinecke wrote:
> + pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL);
> + if (!pg) {
> + sdev_printk(KERN_WARNING, sdev,
> + "%s: kzalloc port group failed\n",
> + ALUA_DH_NAME);
> + /* Temporary failure, bypass */
> + return SCSI_DH_DEV_TEMP_BUSY;
> + }
> + pg->group_id = group_id;
> + pg->buff = pg->inq;
> + pg->bufflen = ALUA_INQUIRY_SIZE;
> + pg->tpgs = h->tpgs;
> + pg->state = TPGS_STATE_OPTIMIZED;
> + kref_init(&pg->kref);
> + spin_lock(&port_group_lock);
> + list_add(&pg->node, &port_group_list);
> + h->pg = pg;
> + spin_unlock(&port_group_lock);
Is there any high level protection against someone racing to allocate
this structure, e.g. from a sysfs-initiated scan?
> - len = (h->buff[0] << 24) + (h->buff[1] << 16) +
> - (h->buff[2] << 8) + h->buff[3] + 4;
> + len = get_unaligned_be32(&pg->buff[0]) + 4;
Andother spurious get/set_unaligned conversion. I'd really recommend doing
all of them before the atual series.
> + rcu_read_lock();
> + pg = rcu_dereference(h->pg);
> + if (!pg) {
> + rcu_read_unlock();
> + return -ENXIO;
> + }
> + rcu_read_unlock();
> +
> if (optimize)
> - h->flags |= ALUA_OPTIMIZE_STPG;
> + pg->flags |= ALUA_OPTIMIZE_STPG;
> else
> - h->flags &= ~ALUA_OPTIMIZE_STPG;
> + pg->flags |= ~ALUA_OPTIMIZE_STPG;
You'll need to move the rcu_read_unlock here to be safe.
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