diff --git a/scst/src/dev_handlers/scst_vdisk.c b/scst/src/dev_handlers/scst_vdisk.c
index d90af2c7f..cbc250a70 100644
--- a/scst/src/dev_handlers/scst_vdisk.c
+++ b/scst/src/dev_handlers/scst_vdisk.c
@@ -456,7 +456,7 @@ static struct kmem_cache *blockio_work_cachep;
 static struct scst_dev_type vdisk_blk_devtype = {
 	.name =			"vdisk_blockio",
 	.type =			TYPE_DISK,
-	.threads_num =		0,
+	.threads_num =		1,
 	.parse_atomic =		1,
 	.dev_done_atomic =	1,
 #ifdef CONFIG_SCST_PROC
@@ -4273,10 +4273,14 @@ static int vdisk_write_proc(char *buffer, char **start, off_t offset,
 			} else if (!strncmp("NULLIO", p, 6)) {
 				p += 6;
 				virt_dev->nullio = 1;
+				/* Bad hack for anyway going out procfs */
+				virt_dev->vdev_devt = &vdisk_null_devtype;
 				TRACE_DBG("%s", "NULLIO");
 			} else if (!strncmp("BLOCKIO", p, 7)) {
 				p += 7;
 				virt_dev->blockio = 1;
+				/* Bad hack for anyway going out procfs */
+				virt_dev->vdev_devt = &vdisk_blk_devtype;
 				TRACE_DBG("%s", "BLOCKIO");
 			} else if (!strncmp("REMOVABLE", p, 9)) {
 				p += 9;
@@ -4313,7 +4317,7 @@ static int vdisk_write_proc(char *buffer, char **start, off_t offset,
 
 		vdisk_report_registering(virt_dev);
 		virt_dev->virt_id = scst_register_virtual_device(
-			dev_type, virt_dev->name);
+			virt_dev->vdev_devt, virt_dev->name);
 		if (virt_dev->virt_id < 0) {
 			res = virt_dev->virt_id;
 			goto out_free_vpath;
diff --git a/scst/src/scst_main.c b/scst/src/scst_main.c
index 7aded3faa..4da1bb466 100644
--- a/scst/src/scst_main.c
+++ b/scst/src/scst_main.c
@@ -1480,10 +1480,18 @@ int scst_add_threads(struct scst_cmd_threads *cmd_threads,
 
 	TRACE_ENTRY();
 
+	if (num == 0) {
+		res = 0;
+		goto out;
+	}
+
 	list_for_each_entry(thr, &cmd_threads->threads_list, thread_list_entry) {
 		n++;
 	}
 
+	TRACE_DBG("cmd_threads %p, dev %p, tgt_dev %p, num %d, n %d",
+		cmd_threads, dev, tgt_dev, num, n);
+
 	if (tgt_dev != NULL) {
 		struct scst_tgt_dev *t;
 		list_for_each_entry(t, &tgt_dev->dev->dev_tgt_dev_list,
@@ -1526,6 +1534,9 @@ int scst_add_threads(struct scst_cmd_threads *cmd_threads,
 		list_add(&thr->thread_list_entry, &cmd_threads->threads_list);
 		cmd_threads->nr_threads++;
 
+		TRACE_DBG("Added thr %p to threads list (nr_threads %d, n %d)",
+			thr, cmd_threads->nr_threads, n);
+
 		wake_up_process(thr->cmd_thread);
 	}
 
@@ -1534,8 +1545,11 @@ int scst_add_threads(struct scst_cmd_threads *cmd_threads,
 		 * Wait for io_context gets initialized to avoid possible races
 		 * for it from the sharing it tgt_devs.
 		 */
-		while (cmd_threads->io_context == NULL)
+		while (cmd_threads->io_context == NULL) {
+			TRACE_DBG("Waiting for io_context for cmd_threads %p "
+				"initialized", cmd_threads);
 			msleep(50);
+		}
 	}
 
 	res = 0;