diff --git a/scst/src/scst_copy_mgr.c b/scst/src/scst_copy_mgr.c
index 96f7ab026..64a0c0c07 100644
--- a/scst/src/scst_copy_mgr.c
+++ b/scst/src/scst_copy_mgr.c
@@ -2498,6 +2498,7 @@ out_free:
 	goto out;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 static bool scst_cm_is_lun_free(unsigned int lun)
 {
 	bool res = true;
@@ -2519,6 +2520,7 @@ static bool scst_cm_is_lun_free(unsigned int lun)
 	return res;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 static unsigned int scst_cm_get_lun(const struct scst_device *dev)
 {
 	unsigned int res = SCST_MAX_LUN;
@@ -2549,6 +2551,7 @@ out:
 	return res;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 static int scst_cm_dev_register(struct scst_device *dev, uint64_t lun)
 {
 	int res, i;
@@ -2628,6 +2631,7 @@ out_err:
 	goto out;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 static void scst_cm_dev_unregister(struct scst_device *dev, bool del_lun)
 {
 	int i;
@@ -2709,6 +2713,7 @@ out_unblock:
 	goto out_resume;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 int scst_cm_on_dev_register(struct scst_device *dev)
 {
 	int res = 0;
@@ -2728,6 +2733,7 @@ out:
 	return res;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 void scst_cm_on_dev_unregister(struct scst_device *dev)
 {
 	TRACE_ENTRY();
@@ -2741,6 +2747,7 @@ void scst_cm_on_dev_unregister(struct scst_device *dev)
 	return;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 int scst_cm_on_add_acg(struct scst_acg *acg)
 {
 	int res = 0;
@@ -2766,6 +2773,7 @@ out:
 	return res;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 void scst_cm_on_del_acg(struct scst_acg *acg)
 {
 	scst_assert_activity_suspended();
@@ -2773,6 +2781,7 @@ void scst_cm_on_del_acg(struct scst_acg *acg)
 	/* Nothing to do */
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 int scst_cm_on_add_lun(struct scst_acg_dev *acg_dev, uint64_t lun,
 	unsigned int *flags)
 {
@@ -2800,6 +2809,7 @@ out:
 	return res;
 }
 
+/* scst_mutex supposed to be held and activities suspended */
 bool scst_cm_on_del_lun(struct scst_acg_dev *acg_dev, bool gen_report_luns_changed)
 {
 	bool res = gen_report_luns_changed;
@@ -2820,6 +2830,7 @@ out:
 	return res;
 }
 
+/* scst_mutex2 supposed to be held */
 static bool scst_cm_check_access_acg(const char *initiator_name,
 	const struct scst_device *dev, const struct scst_acg *acg,
 	bool default_acg)
diff --git a/scst/src/scst_main.c b/scst/src/scst_main.c
index cddb15809..98f7b13f9 100644
--- a/scst/src/scst_main.c
+++ b/scst/src/scst_main.c
@@ -1270,10 +1270,7 @@ static struct scst_device *__scst_lookup_device(struct scsi_device *scsidp)
 	return NULL;
 }
 
-static void scst_unregister_device(struct scsi_device *scsidp,
-				   void (*on_free)(struct scst_device *dev,
-						   void *arg),
-				   void *arg)
+static void scst_unregister_device(struct scsi_device *scsidp)
 {
 	struct scst_device *dev;
 	struct scst_acg_dev *acg_dev, *aa;
@@ -1329,9 +1326,6 @@ static void scst_unregister_device(struct scsi_device *scsidp,
 		   scsidp->host->host_no, scsidp->channel, scsidp->id,
 		   (u64)scsidp->lun, scsidp->type);
 
-	if (on_free)
-		on_free(dev, arg);
-
 	scst_free_device(dev);
 
 out:
@@ -2415,7 +2409,7 @@ static void scst_remove(struct device *cdev, struct class_interface *intf)
 
 	if ((scsidp->host->hostt->name == NULL) ||
 	    (strcmp(scsidp->host->hostt->name, SCST_LOCAL_NAME) != 0))
-		scst_unregister_device(scsidp, NULL, NULL);
+		scst_unregister_device(scsidp);
 
 	TRACE_EXIT();
 	return;
diff --git a/scst/src/scst_targ.c b/scst/src/scst_targ.c
index f02e75e7c..dd392d811 100644
--- a/scst/src/scst_targ.c
+++ b/scst/src/scst_targ.c
@@ -7401,7 +7401,8 @@ static int scst_mgmt_affected_cmds_done(struct scst_mgmt_cmd *mcmd)
 	case SCST_CLEAR_TASK_SET:
 	case SCST_PR_ABORT_ALL:
 	case SCST_LUN_RESET:
-		scst_call_dev_task_mgmt_fn_done(mcmd, mcmd->mcmd_tgt_dev);
+		if (mcmd->mcmd_tgt_dev != NULL)
+			scst_call_dev_task_mgmt_fn_done(mcmd, mcmd->mcmd_tgt_dev);
 		break;
 
 	case SCST_TARGET_RESET: