[SCSI] libsas: remove expander from dev list on error

If expander discovery fails (sas_discover_expander()), remove the
expander from the port device list (sas_ex_discover_expander()),
before freeing it. Else the list is corrupted and, e.g., when we
attempt to send SMP commands to other devices, the kernel oopses.

Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Cc: stable@kernel.org
Reviewed-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/libsas/sas_expander.c

@@ -849,6 +849,9 @@ static struct domain_device *sas_ex_discover_expander(
 
 	res = sas_discover_expander(child);
 	if (res) {
+		spin_lock_irq(&parent->port->dev_list_lock);
+		list_del(&child->dev_list_node);
+		spin_unlock_irq(&parent->port->dev_list_lock);
 		kfree(child);
 		return NULL;
 	}