diff --git a/scst/include/scst.h b/scst/include/scst.h
index 3f6a2e1d1..120df2299 100644
--- a/scst/include/scst.h
+++ b/scst/include/scst.h
@@ -2892,6 +2892,9 @@ struct scst_device {
 	 */
 	struct percpu_ref refcnt;
 
+	/* Triggered when refcnt drops to zero. */
+	struct completion *remove_completion;
+
 	struct work_struct free_work;
 
 	/*
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index 2ce642255..31c8cb443 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -4218,7 +4218,10 @@ static void scst_free_device(struct work_struct *work)
 static void scst_release_device(struct percpu_ref *ref)
 {
 	struct scst_device *dev = container_of(ref, typeof(*dev), refcnt);
+	struct completion *c = dev->remove_completion;
 
+	if (c)
+		complete(c);
 	schedule_work(&dev->free_work);
 }
 
diff --git a/scst/src/scst_main.c b/scst/src/scst_main.c
index afc5f9184..b3a00f745 100644
--- a/scst/src/scst_main.c
+++ b/scst/src/scst_main.c
@@ -1179,6 +1179,7 @@ static void scst_unregister_device(struct scsi_device *scsidp)
 {
 	struct scst_device *dev;
 	struct scst_acg_dev *acg_dev, *aa;
+	DECLARE_COMPLETION_ONSTACK(c);
 
 	TRACE_ENTRY();
 
@@ -1207,6 +1208,8 @@ static void scst_unregister_device(struct scsi_device *scsidp)
 		scst_acg_del_lun(acg_dev->acg, acg_dev->lun, true);
 	}
 
+	dev->remove_completion = &c;
+
 	mutex_unlock(&scst_mutex);
 
 	scst_dev_sysfs_del(dev);
@@ -1218,6 +1221,8 @@ static void scst_unregister_device(struct scsi_device *scsidp)
 	percpu_ref_kill(&dev->refcnt);
 	percpu_ref_put(&dev->refcnt);
 
+	wait_for_completion(&c);
+
 out:
 	TRACE_EXIT();
 	return;
@@ -1441,6 +1446,7 @@ void scst_unregister_virtual_device(int id,
 {
 	struct scst_device *d, *dev = NULL;
 	struct scst_acg_dev *acg_dev, *aa;
+	DECLARE_COMPLETION_ONSTACK(c);
 
 	TRACE_ENTRY();
 
@@ -1473,6 +1479,8 @@ void scst_unregister_virtual_device(int id,
 		scst_acg_del_lun(acg_dev->acg, acg_dev->lun, true);
 	}
 
+	dev->remove_completion = &c;
+
 	mutex_unlock(&scst_mutex);
 
 	scst_dev_sysfs_del(dev);
@@ -1486,6 +1494,8 @@ void scst_unregister_virtual_device(int id,
 	percpu_ref_kill(&dev->refcnt);
 	percpu_ref_put(&dev->refcnt);
 
+	wait_for_completion(&c);
+
 out:
 	TRACE_EXIT();
 	return;
diff --git a/scst/src/scst_sysfs.c b/scst/src/scst_sysfs.c
index 65a1aa9f6..251587150 100644
--- a/scst/src/scst_sysfs.c
+++ b/scst/src/scst_sysfs.c
@@ -1972,6 +1972,8 @@ static ssize_t __scst_acg_cpu_mask_show(struct scst_acg *acg, char *buf)
 #endif
 	if (!cpumask_equal(&acg->acg_cpu_mask, &default_cpu_mask))
 		res += sprintf(&buf[res], "\n%s\n", SCST_SYSFS_KEY_MARK);
+	else
+		res += sprintf(&buf[res], "\n");
 
 	return res;
 }