diff --git a/doc/KUNIT.md b/doc/KUNIT.md
index 4b8a96c7d..11427d7da 100644
--- a/doc/KUNIT.md
+++ b/doc/KUNIT.md
@@ -60,7 +60,7 @@ validates the selection against the supplied `.ko` files.
 
 | Module | Labels |
 | --- | --- |
-| `scst.ko` | `ALUA CDB EVENT LIB ORDER UNMAP` |
+| `scst.ko` | `ALUA CDB CM EVENT LIB ORDER UNMAP` |
 
 The runner reads suite metadata from the modules and loads selected owners
 with their dependencies. Unselected suites are not counted as skipped.
diff --git a/scripts/generate-kernel-patch b/scripts/generate-kernel-patch
index aa04256af..bdcd26544 100755
--- a/scripts/generate-kernel-patch
+++ b/scripts/generate-kernel-patch
@@ -311,7 +311,8 @@ scst_04_main="scst/src/scst_main.c scst/src/scst_priv.h \
 scst/src/scst_copy_mgr.c scst/src/scst_dlm.c scst/src/scst_dlm.h \
 scst/src/scst_event.c scst/src/scst_event_priv.h scst/src/scst_no_dlm.c \
 scst/src/scst_test.h \
-scst/src/scst_event_test.h"
+scst/src/scst_event_test.h \
+scst/src/scst_copy_mgr_test.h"
 scst_05_targ="scst/src/scst_targ.c scst/src/scst_local_cmd.c \
 scst/src/scst_local_cmd.h \
 scst/src/scst_targ_test.h"
diff --git a/scst/src/kunit/cm/suites/scst_kunit_cm.c b/scst/src/kunit/cm/suites/scst_kunit_cm.c
new file mode 100644
index 000000000..521b7514e
--- /dev/null
+++ b/scst/src/kunit/cm/suites/scst_kunit_cm.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "../../scst_kunit.h"
+
+#ifdef INSIDE_KERNEL_TREE
+#include <scst/scst.h>
+#else
+#include "scst.h"
+#endif
+#include "../../../scst_priv.h"
+#include "../../../scst_copy_mgr_test.h"
+
+struct cm_fixture {
+	struct scst_device dev;
+	struct scst_acg acg;
+	struct scst_acg other_acg;
+	struct scst_acg_dev acg_dev;
+	unsigned int registrations;
+	int register_result;
+	struct completion removing;
+	unsigned int lun;
+	unsigned int lookups;
+	unsigned int designator_clears;
+	unsigned int inquiries;
+	int inquiry_result;
+};
+
+static unsigned int cm_lookup_stub(const struct scst_device *dev)
+{
+	struct kunit *test = kunit_get_current_test();
+	struct cm_fixture *f = test->priv;
+
+	KUNIT_EXPECT_PTR_EQ(test, dev, &f->dev);
+	KUNIT_EXPECT_TRUE(test, mutex_is_locked(&scst_mutex));
+	lockdep_assert_held(&scst_mutex);
+	f->lookups++;
+	return f->lun;
+}
+
+static void cm_clear_stub(struct scst_device *dev)
+{
+	struct kunit *test = kunit_get_current_test();
+	struct cm_fixture *f = test->priv;
+
+	KUNIT_EXPECT_PTR_EQ(test, dev, &f->dev);
+	KUNIT_EXPECT_TRUE(test, mutex_is_locked(&scst_mutex));
+	f->designator_clears++;
+}
+
+static int cm_inquiry_stub(struct scst_device *dev, unsigned int lun,
+			   struct scst_cm_init_inq_priv *priv)
+{
+	struct kunit *test = kunit_get_current_test();
+	struct cm_fixture *f = test->priv;
+
+	KUNIT_EXPECT_PTR_EQ(test, dev, &f->dev);
+	KUNIT_EXPECT_PTR_EQ(test, priv, NULL);
+	KUNIT_EXPECT_EQ(test, lun, f->lun);
+	KUNIT_EXPECT_GT(test, dev->block_count, 0);
+	KUNIT_EXPECT_TRUE(test, mutex_is_locked(&scst_mutex));
+	KUNIT_EXPECT_EQ(test, f->designator_clears, f->inquiries + 1);
+	f->inquiries++;
+	return f->inquiry_result;
+}
+
+static int cm_test_init(struct kunit *test)
+{
+	struct cm_fixture *f;
+
+	f = kunit_kzalloc(test, sizeof(*f), GFP_KERNEL);
+	if (!f)
+		return -ENOMEM;
+	test->priv = f;
+	f->dev.virt_name = "kunit-private-cm-device";
+	spin_lock_init(&f->dev.dev_lock);
+	INIT_LIST_HEAD(&f->dev.blocked_cmd_list);
+	atomic_set(&f->dev.cm_update_req_cnt, 0);
+	init_completion(&f->removing);
+	f->lun = 9;
+	kunit_activate_static_stub(test, scst_cm_get_lun, cm_lookup_stub);
+	kunit_activate_static_stub(test, scst_cm_dev_free_designators, cm_clear_stub);
+	kunit_activate_static_stub(test, scst_cm_send_init_inquiry, cm_inquiry_stub);
+	return 0;
+}
+
+struct cm_update_case {
+	const char *name;
+	unsigned int pending;
+	int error;
+	bool removing;
+	int initial_blocks;
+};
+
+static const struct cm_update_case cm_updates[] = {
+	{ "single", 0 },
+	{ "coalesce-two", 1 },
+	{ "coalesce-many", 10 },
+	{ "inquiry-enomem", 0, -ENOMEM },
+	{ "inquiry-eio", 0, -EIO },
+	{ "preserve-existing-block", 0, -ENOMEM, false, 1 },
+	{ "unregistered-before-update", 0, 0, true },
+	{ "unregistered-before-retry", 3, 0, true },
+	{ "retry-enomem", 3, -ENOMEM },
+	{ "retry-eio", 3, -EIO },
+};
+
+static void cm_update_desc(const struct cm_update_case *p, char *desc)
+{
+	strscpy(desc, p->name, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(cm_update, cm_updates, cm_update_desc);
+
+static void cm_update_test(struct kunit *test)
+{
+	const struct cm_update_case *p = test->param_value;
+	struct cm_fixture *f = test->priv;
+	unsigned int i;
+
+	f->dev.block_count = p->initial_blocks;
+	if (!p->pending) {
+		f->inquiry_result = p->error;
+		if (p->removing) {
+			f->lun = SCST_MAX_LUN;
+			f->dev.remove_completion = &f->removing;
+		}
+	}
+	scst_cm_update_dev_start(&f->dev);
+	if (p->pending) {
+		KUNIT_ASSERT_EQ(test, f->inquiries, 1U);
+		for (i = 0; i < p->pending; i++)
+			scst_cm_update_dev_start(&f->dev);
+		KUNIT_EXPECT_EQ(test, f->inquiries, 1U);
+		KUNIT_EXPECT_EQ(test, atomic_read(&f->dev.cm_update_req_cnt), (int)p->pending + 1);
+		/* The real inquiry completion unblocks before calling update_fini. */
+		spin_lock_bh(&f->dev.dev_lock);
+		scst_unblock_dev(&f->dev);
+		spin_unlock_bh(&f->dev.dev_lock);
+		f->inquiry_result = p->error;
+		if (p->removing) {
+			f->lun = SCST_MAX_LUN;
+			f->dev.remove_completion = &f->removing;
+		}
+		scst_cm_update_dev_fini(&f->dev);
+	}
+	KUNIT_EXPECT_EQ(test, f->lookups, p->pending ? 2U : 1U);
+	KUNIT_EXPECT_EQ(test, f->inquiries,
+			(unsigned int)!p->removing + (unsigned int)!!p->pending);
+	if (p->error || p->removing) {
+		KUNIT_EXPECT_EQ(test, f->dev.block_count, p->initial_blocks);
+		KUNIT_EXPECT_EQ(test, atomic_read(&f->dev.cm_update_req_cnt), 0);
+	} else {
+		KUNIT_EXPECT_EQ(test, atomic_read(&f->dev.cm_update_req_cnt), 1);
+		spin_lock_bh(&f->dev.dev_lock);
+		scst_unblock_dev(&f->dev);
+		spin_unlock_bh(&f->dev.dev_lock);
+		scst_cm_update_dev_fini(&f->dev);
+		KUNIT_EXPECT_EQ(test, atomic_read(&f->dev.cm_update_req_cnt), 0);
+		KUNIT_EXPECT_EQ(test, f->dev.block_count, p->initial_blocks);
+	}
+	KUNIT_EXPECT_EQ(test, f->designator_clears, f->inquiries);
+	KUNIT_EXPECT_FALSE(test, completion_done(&f->removing));
+}
+
+static struct scst_acg *cm_default_group(void)
+{
+	struct cm_fixture *f = kunit_get_current_test()->priv;
+
+	return &f->acg;
+}
+
+static int cm_register_stub(struct scst_device *dev, uint64_t lun)
+{
+	struct kunit *test = kunit_get_current_test();
+	struct cm_fixture *f = test->priv;
+
+	KUNIT_EXPECT_PTR_EQ(test, dev, &f->dev);
+	KUNIT_EXPECT_EQ(test, lun, (u64)9);
+	lockdep_assert_held(&scst_mutex);
+	f->registrations++;
+	return f->register_result;
+}
+
+struct cm_lun_case {
+	const char *name;
+	bool foreign;
+	bool lun_readonly;
+	bool dev_readonly;
+	int register_error;
+};
+
+static const struct cm_lun_case cm_luns[] = {
+	{ "foreign-writable", true },
+	{ "foreign-readonly", true, true, true },
+	{ "readonly-lun", false, true },
+	{ "readonly-device", false, false, true },
+	{ "readonly-both", false, true, true },
+	{ "writable" },
+	{ "register-enomem", false, false, false, -ENOMEM },
+	{ "register-eio", false, false, false, -EIO },
+};
+
+static void cm_lun_desc(const struct cm_lun_case *p, char *desc)
+{
+	strscpy(desc, p->name, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(cm_lun, cm_luns, cm_lun_desc);
+
+static void cm_lun_test(struct kunit *test)
+{
+	const struct cm_lun_case *p = test->param_value;
+	struct cm_fixture *f = test->priv;
+	unsigned int flags = SCST_ADD_LUN_GEN_UA | SCST_ADD_LUN_READ_ONLY;
+	bool readonly = p->lun_readonly || p->dev_readonly;
+	bool registered = !p->foreign && !readonly;
+	int rc;
+
+	f->acg_dev.acg = p->foreign ? &f->other_acg : &f->acg;
+	f->acg_dev.dev = &f->dev;
+	f->acg_dev.acg_dev_rd_only = p->lun_readonly;
+	f->dev.dev_rd_only = p->dev_readonly;
+	f->register_result = p->register_error;
+	kunit_activate_static_stub(test, scst_cm_default_acg, cm_default_group);
+	kunit_activate_static_stub(test, scst_cm_dev_register, cm_register_stub);
+	mutex_lock(&scst_mutex);
+	rc = scst_cm_on_add_lun(&f->acg_dev, 9, &flags);
+	mutex_unlock(&scst_mutex);
+	KUNIT_EXPECT_EQ(test, rc, p->foreign ? 0 : (readonly ? -EINVAL : p->register_error));
+	KUNIT_EXPECT_EQ(test, f->registrations, (unsigned int)registered);
+	KUNIT_EXPECT_EQ(test, !!(flags & SCST_ADD_LUN_GEN_UA), !registered);
+	KUNIT_EXPECT_TRUE(test, !!(flags & SCST_ADD_LUN_READ_ONLY));
+}
+
+static struct kunit_case cm_cases[] = {
+	KUNIT_CASE_PARAM(cm_update_test, cm_update_gen_params),
+	KUNIT_CASE_PARAM(cm_lun_test, cm_lun_gen_params),
+	{}
+};
+
+scst_kunit_suite(cm_suite, "CM", "",
+		 .init = cm_test_init,
+		 .test_cases = cm_cases,
+);
diff --git a/scst/src/kunit/objects.mk b/scst/src/kunit/objects.mk
index d4bf3f19f..5fc3e86d5 100644
--- a/scst/src/kunit/objects.mk
+++ b/scst/src/kunit/objects.mk
@@ -4,6 +4,7 @@
 scst-kunit-scst := \
 	kunit/alua/suites/scst_kunit_alua.o \
 	kunit/cdb/suites/scst_kunit_cdb.o \
+	kunit/cm/suites/scst_kunit_cm.o \
 	kunit/event/scst_event_fixture.o \
 	kunit/event/suites/scst_kunit_event_import.o \
 	kunit/event/suites/scst_kunit_event_delivery.o \
diff --git a/scst/src/scst_copy_mgr.c b/scst/src/scst_copy_mgr.c
index 520c71155..797b76e76 100644
--- a/scst/src/scst_copy_mgr.c
+++ b/scst/src/scst_copy_mgr.c
@@ -17,6 +17,15 @@
 #endif
 #include "scst_priv.h"
 #include "scst_pres.h"
+#include "scst_copy_mgr_test.h"
+
+#ifndef SCST_KUNIT_ENABLED
+struct scst_cm_init_inq_priv;
+
+static int scst_cm_send_init_inquiry(struct scst_device *dev, unsigned int unpacked_lun,
+				     struct scst_cm_init_inq_priv *priv);
+static void scst_cm_update_dev_fini(struct scst_device *dev);
+#endif
 
 #undef DEFAULT_SYMBOL_NAMESPACE
 #define DEFAULT_SYMBOL_NAMESPACE	SCST_NAMESPACE
@@ -2238,9 +2247,6 @@ struct scst_cm_init_inq_priv {
 	struct scst_device *dev;
 };
 
-static int scst_cm_send_init_inquiry(struct scst_device *dev, unsigned int unpacked_lun,
-				     struct scst_cm_init_inq_priv *priv);
-
 static void scst_cm_inq_retry_fn(struct scst_cmd *cmd)
 {
 	struct scst_cm_init_inq_priv *priv = cmd->tgt_i_priv;
@@ -2254,8 +2260,6 @@ static void scst_cm_inq_retry_fn(struct scst_cmd *cmd)
 	TRACE_EXIT();
 }
 
-static void scst_cm_update_dev_fini(struct scst_device *dev);
-
 static void scst_cm_init_inq_finish(struct scst_cmd *cmd)
 {
 	int length, page_len, off, rc;
@@ -2380,14 +2384,17 @@ out:
 	TRACE_EXIT();
 }
 
-static int scst_cm_send_init_inquiry(struct scst_device *dev, unsigned int unpacked_lun,
-				     struct scst_cm_init_inq_priv *priv)
+SCST_KUNIT_VISIBLE
+int scst_cm_send_init_inquiry(struct scst_device *dev, unsigned int unpacked_lun,
+			      struct scst_cm_init_inq_priv *priv)
 {
 	static const uint8_t inq_cdb[6] = { INQUIRY, 1, 0x83, 0x10, 0, 0 };
 	__be64 lun;
 	struct scst_cmd *cmd;
 	int res = 0;
 
+	SCST_KUNIT_REDIRECT(scst_cm_send_init_inquiry, dev, unpacked_lun, priv);
+
 	TRACE_ENTRY();
 
 	if (WARN_ON_ONCE(!dev)) {
@@ -2458,11 +2465,14 @@ static bool scst_cm_is_lun_free(unsigned int lun)
 }
 
 /* scst_mutex supposed to be held */
-static unsigned int scst_cm_get_lun(const struct scst_device *dev)
+SCST_KUNIT_VISIBLE
+unsigned int scst_cm_get_lun(const struct scst_device *dev)
 {
 	unsigned int res = SCST_MAX_LUN;
 	int i;
 
+	SCST_KUNIT_REDIRECT(scst_cm_get_lun, dev);
+
 	TRACE_ENTRY();
 
 	rcu_read_lock();
@@ -2506,11 +2516,14 @@ static uint64_t scst_cm_get_free_lun(void)
 	return lun;
 }
 
-static int scst_cm_dev_register(struct scst_device *dev, uint64_t lun)
+SCST_KUNIT_VISIBLE
+int scst_cm_dev_register(struct scst_device *dev, uint64_t lun)
 {
 	int res;
 	struct scst_acg_dev *acg_dev;
 
+	SCST_KUNIT_REDIRECT(scst_cm_dev_register, dev, lun);
+
 	TRACE_ENTRY();
 
 	lockdep_assert_held(&scst_mutex);
@@ -2561,10 +2574,13 @@ out_err:
 	goto out;
 }
 
-static void scst_cm_dev_free_designators(struct scst_device *dev)
+SCST_KUNIT_VISIBLE
+void scst_cm_dev_free_designators(struct scst_device *dev)
 {
 	struct scst_cm_desig *des, *t;
 
+	SCST_KUNIT_REDIRECT(scst_cm_dev_free_designators, dev);
+
 	TRACE_ENTRY();
 
 	mutex_lock(&scst_cm_mutex);
@@ -2648,8 +2664,8 @@ out_unblock:
 	goto out_unlock;
 }
 
-static void
-scst_cm_update_dev_start(struct scst_device *dev)
+SCST_KUNIT_VISIBLE
+void scst_cm_update_dev_start(struct scst_device *dev)
 {
 	int update_req_cnt, rc;
 
@@ -2662,8 +2678,8 @@ scst_cm_update_dev_start(struct scst_device *dev)
 		atomic_set(&dev->cm_update_req_cnt, 0);
 }
 
-static void
-scst_cm_update_dev_fini(struct scst_device *dev)
+SCST_KUNIT_VISIBLE
+void scst_cm_update_dev_fini(struct scst_device *dev)
 {
 	int update_req_cnt, rc;
 
@@ -2765,6 +2781,13 @@ void scst_cm_on_del_acg(struct scst_acg *acg)
 	/* Nothing to do */
 }
 
+SCST_KUNIT_VISIBLE
+struct scst_acg *scst_cm_default_acg(void)
+{
+	SCST_KUNIT_REDIRECT(scst_cm_default_acg);
+	return scst_cm_tgt->default_acg;
+}
+
 /* scst_mutex supposed to be held */
 int scst_cm_on_add_lun(struct scst_acg_dev *acg_dev, uint64_t lun, unsigned int *flags)
 {
@@ -2774,7 +2797,7 @@ int scst_cm_on_add_lun(struct scst_acg_dev *acg_dev, uint64_t lun, unsigned int
 
 	lockdep_assert_held(&scst_mutex);
 
-	if (acg_dev->acg != scst_cm_tgt->default_acg)
+	if (acg_dev->acg != scst_cm_default_acg())
 		goto out;
 
 	if (acg_dev->acg_dev_rd_only || acg_dev->dev->dev_rd_only) {
diff --git a/scst/src/scst_copy_mgr_test.h b/scst/src/scst_copy_mgr_test.h
new file mode 100644
index 000000000..e93e7f9d9
--- /dev/null
+++ b/scst/src/scst_copy_mgr_test.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SCST_COPY_MGR_TEST_H
+#define SCST_COPY_MGR_TEST_H
+
+#include "scst_test.h"
+
+#ifdef SCST_KUNIT_ENABLED
+
+struct scst_cm_init_inq_priv;
+
+int scst_cm_send_init_inquiry(struct scst_device *dev, unsigned int unpacked_lun,
+			      struct scst_cm_init_inq_priv *priv);
+unsigned int scst_cm_get_lun(const struct scst_device *dev);
+int scst_cm_dev_register(struct scst_device *dev, uint64_t lun);
+void scst_cm_dev_free_designators(struct scst_device *dev);
+void scst_cm_update_dev_start(struct scst_device *dev);
+void scst_cm_update_dev_fini(struct scst_device *dev);
+struct scst_acg *scst_cm_default_acg(void);
+
+#endif /* SCST_KUNIT_ENABLED */
+#endif /* SCST_COPY_MGR_TEST_H */