From d58fdbe37a829fd2e5803dd4e5a72992dd8c5368 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Wed, 17 Jun 2026 17:56:47 -0700 Subject: [PATCH] mm/damon/sysfs-schemes: fix dir put orders in access_pattern_add_dirs() Patch series "mm/damon/sysfs-schemes: fix wrong directories put orders in error paths". Error paths of damon_sysfs_access_pattern_add_dirs() and damon_sysfs_scheme_add_dirs() functions put references to directories in wrong orders. As a result, uninitialized memory dereference and/or memory leak can happen. Fix those. This patch (of 2): 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. Link: https://lore.kernel.org/20260618005650.83868-2-sj@kernel.org Link: https://lore.kernel.org/20260617060005.86852-1-sj@kernel.org [1] Fixes: 7e84b1f8212a ("mm/damon/sysfs: support DAMON-based Operation Schemes") Signed-off-by: SeongJae Park Cc: # 5.18.x Signed-off-by: Andrew Morton --- 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 329cfd0bbe9f..7c00aa78b2f5 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;