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

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

[Zenghui Yu]

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

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

[SJ Park]

On Mon,  7 Sep 2026 20:34:55 +0800 Zenghui Yu <zenghui.yu@linux.dev> wrote:

> 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.

Looks good to me, thank you for fixing this, Zenghui.

> 
> 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>

Reviewed-by: SJ Park <sj@kernel.org>

This patch is applied to damon/next [1] tree.  If this patch is not added to
mm.git in short term (~1 week?), I will ask mm.git maintainer (Andrew Morton)
to pick this.  So, no action from your side is needed for now.  If it seems I
also forgot doing that or you cannot wait for my action, please feel free to
directly ask that to Andrew.

[1] https://origin.kernel.org/doc/html/latest/mm/damon/maintainer-profile.html#scm-trees


Thanks,
SJ

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