[PATCH] selftests/damon: stop kdamond on error exits of no-op commit test

[Zenghui Yu <zenghui.yu@linux.dev>]

From: "Zenghui Yu (Huawei)" <zenghui.yu@linux.dev>

The sysfs_no_op_commit_break test starts a kdamond via sysfs, but its error
paths (e.g., drgn not installed) exit without stopping it.  The leaked
kdamond then makes subsequent tests, e.g. lru_sort.sh and reclaim.sh, skip
with "Another kdamond is running".

Wrap the post-start logic in try-finally so that kdamonds.stop() is
executed on every exit path.

Fixes: 10725cd2b09a ("selftests/damon: test no-op commit broke DAMON status")
Assisted-by: GLM-5.3 OpenCode
Signed-off-by: Zenghui Yu (Huawei) <zenghui.yu@linux.dev>
---
 .../damon/sysfs_no_op_commit_break.py         | 35 ++++++++++---------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/tools/testing/selftests/damon/sysfs_no_op_commit_break.py b/tools/testing/selftests/damon/sysfs_no_op_commit_break.py
index 2c65cffe6b54..81774ddc55ac 100755
--- a/tools/testing/selftests/damon/sysfs_no_op_commit_break.py
+++ b/tools/testing/selftests/damon/sysfs_no_op_commit_break.py
@@ -47,26 +47,27 @@ def main():
         print('kdamond start failed: %s' % err)
         exit(1)
 
-    before_commit_status, err = \
-        dump_damon_status_dict(kdamonds.kdamonds[0].pid)
-    if err is not None:
-        print('before-commit status dump failed: %s' % err)
-        exit(1)
+    try:
+        before_commit_status, err = \
+            dump_damon_status_dict(kdamonds.kdamonds[0].pid)
+        if err is not None:
+            print('before-commit status dump failed: %s' % err)
+            exit(1)
 
-    kdamonds.kdamonds[0].commit()
+        kdamonds.kdamonds[0].commit()
 
-    after_commit_status, err = \
-        dump_damon_status_dict(kdamonds.kdamonds[0].pid)
-    if err is not None:
-        print('after-commit status dump failed: %s' % err)
-        exit(1)
-
-    if before_commit_status != after_commit_status:
-        print(f'before: {json.dumps(before_commit_status, indent=2)}')
-        print(f'after: {json.dumps(after_commit_status, indent=2)}')
-        exit(1)
+        after_commit_status, err = \
+            dump_damon_status_dict(kdamonds.kdamonds[0].pid)
+        if err is not None:
+            print('after-commit status dump failed: %s' % err)
+            exit(1)
 
-    kdamonds.stop()
+        if before_commit_status != after_commit_status:
+            print(f'before: {json.dumps(before_commit_status, indent=2)}')
+            print(f'after: {json.dumps(after_commit_status, indent=2)}')
+            exit(1)
+    finally:
+        kdamonds.stop()
 
 if __name__ == '__main__':
     main()
-- 
2.53.0