[PATCH blktests] dm: add a regression test

[Yu Kuai <yukuai1@huaweicloud.com>]

From: Yu Kuai <yukuai3@huawei.com>

Verify that reload a dm with itself won't crash the kernel.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 tests/dm/001     | 27 +++++++++++++++++++++++++++
 tests/dm/001.out |  4 ++++
 tests/dm/rc      | 11 +++++++++++
 3 files changed, 42 insertions(+)
 create mode 100755 tests/dm/001
 create mode 100644 tests/dm/001.out
 create mode 100644 tests/dm/rc

diff --git a/tests/dm/001 b/tests/dm/001
new file mode 100755
index 0000000..55e07f3
--- /dev/null
+++ b/tests/dm/001
@@ -0,0 +1,27 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2022 Yu Kuai
+#
+# Regression test for commit 077a4033541f ("block: don't allow a disk link
+# holder to itself")
+
+. tests/dm/rc
+
+DESCRIPTION="reload a dm with itself"
+QUICK=1
+
+requires() {
+	_have_program dmsetup && _have_driver dm-mod
+}
+
+test_device() {
+	echo "Running ${TEST_NAME}"
+
+	dmsetup create test --table "0 8192 linear ${TEST_DEV} 0"
+	dmsetup suspend test
+	dmsetup reload test --table "0 8192 linear /dev/mapper/test 0"
+	dmsetup resume test
+	dmsetup remove test
+
+	echo "Test complete"
+}
diff --git a/tests/dm/001.out b/tests/dm/001.out
new file mode 100644
index 0000000..23cf1f0
--- /dev/null
+++ b/tests/dm/001.out
@@ -0,0 +1,4 @@
+Running dm/001
+device-mapper: reload ioctl on test failed: Invalid argument
+Command failed
+Test complete
diff --git a/tests/dm/rc b/tests/dm/rc
new file mode 100644
index 0000000..e1ad6c6
--- /dev/null
+++ b/tests/dm/rc
@@ -0,0 +1,11 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2022 Yu Kuai
+#
+# TODO: provide a brief description of the group here.
+
+. common/rc
+
+group_requires() {
+	_have_root
+}
-- 
2.31.1