[PATCH 1/7] selftest/damon: add a test for duplicate context dirs creation

[SeongJae Park]

Commit d26f60703606 ("mm/damon/dbgfs: avoid duplicate context directory
creation") fixes a bug which could result in memory leak and DAMON
disablement.  This commit adds a selftest for verifying the fix and
avoid regression.

Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
 tools/testing/selftests/damon/Makefile        |  1 +
 .../debugfs_duplicate_context_creation.sh     | 27 +++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 tools/testing/selftests/damon/debugfs_duplicate_context_creation.sh

diff --git a/tools/testing/selftests/damon/Makefile b/tools/testing/selftests/damon/Makefile
index 0470c5f3e690..a1fa2eff8192 100644
--- a/tools/testing/selftests/damon/Makefile
+++ b/tools/testing/selftests/damon/Makefile
@@ -6,6 +6,7 @@ TEST_GEN_FILES += huge_count_read_write
 TEST_FILES = _chk_dependency.sh _debugfs_common.sh
 TEST_PROGS = debugfs_attrs.sh debugfs_schemes.sh debugfs_target_ids.sh
 TEST_PROGS += debugfs_empty_targets.sh debugfs_huge_count_read_write.sh
+TEST_PROGS += debugfs_duplicate_context_creation.sh
 TEST_PROGS += sysfs.sh
 
 include ../lib.mk
diff --git a/tools/testing/selftests/damon/debugfs_duplicate_context_creation.sh b/tools/testing/selftests/damon/debugfs_duplicate_context_creation.sh
new file mode 100644
index 000000000000..4a76e37ef16b
--- /dev/null
+++ b/tools/testing/selftests/damon/debugfs_duplicate_context_creation.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source _debugfs_common.sh
+
+# Test duplicated context creation
+# ================================
+
+if ! echo foo > "$DBGFS/mk_contexts"
+then
+	echo "context creation failed"
+	exit 1
+fi
+
+if echo foo > "$DBGFS/mk_contexts"
+then
+	echo "duplicate context creation success"
+	exit 1
+fi
+
+if ! echo foo > "$DBGFS/rm_contexts"
+then
+	echo "context deletion failed"
+	exit 1
+fi
+
+exit 0
-- 
2.25.1