[PATCH] selftests/damon: check correct path in ensure_file() not_exist case

[PATCH] selftests/damon: check correct path in ensure_file() not_exist case

[wang wei]

In the ensure_file() function, the "not_exist" code path checks
whether $dir exists as a regular file.  However, the intent is to
verify that the target file ($file) does not exist, not the $dir.
Testing $dir makes the existence check effectively useless --
it tests the wrong path and thus never catches the case
where the file is unexpectedly present.

Replace $dir with $file so the not_exist verification targets the
correct path.

Signed-off-by: wang wei <a929244872@163.com>
---
 tools/testing/selftests/damon/sysfs.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index 78f4badb5..bf4684d36 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -67,7 +67,7 @@ ensure_file()
 			echo "$file permission: expected $permission but $perm"
 			exit 1
 		fi
-	elif [ "$to_ensure" = "not_exist" ] && [ -f "$dir" ]
+	elif [ "$to_ensure" = "not_exist" ] && [ -f "$file" ]
 	then
 		echo "$file is not expected but found"
 		exit 1
-- 
2.43.0

Re: [PATCH] selftests/damon: check correct path in ensure_file() not_exist case

[SJ Park]

+ Andrew

On Mon,  6 Jul 2026 21:43:04 +0800 wang wei <a929244872@163.com> wrote:

> In the ensure_file() function, the "not_exist" code path checks
> whether $dir exists as a regular file.  However, the intent is to
> verify that the target file ($file) does not exist, not the $dir.
> Testing $dir makes the existence check effectively useless --
> it tests the wrong path and thus never catches the case
> where the file is unexpectedly present.
> 
> Replace $dir with $file so the not_exist verification targets the
> correct path.

Nice catch, thank you!

> 
> Signed-off-by: wang wei <a929244872@163.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

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