[PATCH 1/2] mm/damon/sysfs-schemes: fix dir put orders in access_pattern_add_dirs()

[SeongJae Park]

In access_pattern_add_dirs(), error handling path puts references
starting from setup failed directories.  If the failure happpened from
the initial allication in the setup functions, uninitialized memory
dereference happen.  The allocation failures will not commonly happen,
but the consequence is quite bad.  Fix the wrong reference put orders.

The issue was discovered [1] by Sashiko.

[1] https://lore.kernel.org/20260617060005.86852-1-sj@xxxxxxxxxx

Fixes: 7e84b1f8212a ("mm/damon/sysfs: support DAMON-based Operation Schemes")
Cc: <stable@xxxxxxxxxxxxxxx> # 5.18.x
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
 mm/damon/sysfs-schemes.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 329cfd0bbe9f3..7c00aa78b2f50 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1993,22 +1993,19 @@ static int damon_sysfs_access_pattern_add_dirs(
 	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
 			&access_pattern->sz, "sz");
 	if (err)
-		goto put_sz_out;
+		return err;
 
 	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
 			&access_pattern->nr_accesses, "nr_accesses");
 	if (err)
-		goto put_nr_accesses_sz_out;
+		goto put_sz_out;
 
 	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
 			&access_pattern->age, "age");
 	if (err)
-		goto put_age_nr_accesses_sz_out;
+		goto put_nr_accesses_sz_out;
 	return 0;
 
-put_age_nr_accesses_sz_out:
-	kobject_put(&access_pattern->age->kobj);
-	access_pattern->age = NULL;
 put_nr_accesses_sz_out:
 	kobject_put(&access_pattern->nr_accesses->kobj);
 	access_pattern->nr_accesses = NULL;
-- 
2.47.3