Running these tests under Python's safe path mode, either with -P on the
interpreter command line or with PYTHONSAFEPATH set in the environment,
stops the script's own directory being prepended to sys.path. Some
distributions (RHEL, for example) build the tests with -P in the shebang.

This breaks all 7 DAMON Python selftests that import the _damon_sysfs
helper module located in the same directory:

  ModuleNotFoundError: No module named '_damon_sysfs'

Fix this by explicitly adding the script's directory to sys.path before
importing _damon_sysfs, following the same pattern used in commit
c3b3eb565bd7 ("tools: ynl: add script dir to sys.path") which fixed the
identical issue for the YNL tools.

Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
---
 tools/testing/selftests/damon/damon_nr_regions.py              | 3 +++
 tools/testing/selftests/damon/damos_apply_interval.py          | 3 +++
 tools/testing/selftests/damon/damos_quota.py                   | 3 +++
 tools/testing/selftests/damon/damos_quota_goal.py              | 3 +++
 tools/testing/selftests/damon/damos_tried_regions.py           | 3 +++
 .../selftests/damon/sysfs_update_schemes_tried_regions_hang.py | 3 +++
 .../damon/sysfs_update_schemes_tried_regions_wss_estimation.py | 3 +++
 7 files changed, 21 insertions(+)

diff --git a/tools/testing/selftests/damon/damon_nr_regions.py b/tools/testing/selftests/damon/damon_nr_regions.py
index 58f3291fed12..e55239813c65 100755
--- a/tools/testing/selftests/damon/damon_nr_regions.py
+++ b/tools/testing/selftests/damon/damon_nr_regions.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+import os
 import subprocess
+import sys
 import time
 
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 import _damon_sysfs
 
 def test_nr_regions(real_nr_regions, min_nr_regions, max_nr_regions):
diff --git a/tools/testing/selftests/damon/damos_apply_interval.py b/tools/testing/selftests/damon/damos_apply_interval.py
index 0f2f36584e48..0bf7768b2006 100755
--- a/tools/testing/selftests/damon/damos_apply_interval.py
+++ b/tools/testing/selftests/damon/damos_apply_interval.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+import os
 import subprocess
+import sys
 import time
 
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 import _damon_sysfs
 
 def main():
diff --git a/tools/testing/selftests/damon/damos_quota.py b/tools/testing/selftests/damon/damos_quota.py
index 57c4937aaed2..879115a499bf 100755
--- a/tools/testing/selftests/damon/damos_quota.py
+++ b/tools/testing/selftests/damon/damos_quota.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+import os
 import subprocess
+import sys
 import time
 
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 import _damon_sysfs
 
 def main():
diff --git a/tools/testing/selftests/damon/damos_quota_goal.py b/tools/testing/selftests/damon/damos_quota_goal.py
index 661e4ba4765a..fed033a0afdf 100755
--- a/tools/testing/selftests/damon/damos_quota_goal.py
+++ b/tools/testing/selftests/damon/damos_quota_goal.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+import os
 import subprocess
+import sys
 import time
 
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 import _damon_sysfs
 
 def main():
diff --git a/tools/testing/selftests/damon/damos_tried_regions.py b/tools/testing/selftests/damon/damos_tried_regions.py
index d6472e6a6e08..6941f87c10b1 100755
--- a/tools/testing/selftests/damon/damos_tried_regions.py
+++ b/tools/testing/selftests/damon/damos_tried_regions.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+import os
 import subprocess
+import sys
 import time
 
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 import _damon_sysfs
 
 def main():
diff --git a/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_hang.py b/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_hang.py
index 28c887a0108f..625761c243b5 100755
--- a/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_hang.py
+++ b/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_hang.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+import os
 import subprocess
+import sys
 import time
 
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 import _damon_sysfs
 
 def main():
diff --git a/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py b/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py
index 16fdc6e7fc56..36e7ae5f826d 100755
--- a/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py
+++ b/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py
@@ -1,9 +1,12 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
+import os
 import subprocess
+import sys
 import time
 
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
 import _damon_sysfs
 
 def pass_wss_estimation(sz_region):
-- 
2.55.0

On Wed,  9 Sep 2026 00:42:35 +0300 Eva Kurchatova <eva.kurchatova@virtuozzo.com> wrote:

> Running these tests under Python's safe path mode, either with -P on the
> interpreter command line or with PYTHONSAFEPATH set in the environment,
> stops the script's own directory being prepended to sys.path. Some
> distributions (RHEL, for example) build the tests with -P in the shebang.
> 
> This breaks all 7 DAMON Python selftests that import the _damon_sysfs
> helper module located in the same directory:
> 
>   ModuleNotFoundError: No module named '_damon_sysfs'
> 
> Fix this by explicitly adding the script's directory to sys.path before
> importing _damon_sysfs, following the same pattern used in commit
> c3b3eb565bd7 ("tools: ynl: add script dir to sys.path") which fixed the
> identical issue for the YNL tools.

Thank you for finding and fixing this, Eva!

> 
> Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>

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

[...]