[PATCH v2] mm: huge_memory: Fix kobject cleanup in thpsize_create error

[Hongling Zeng]

When kobject_init_and_add() fails, the kobject API requires calling
kobject_put() to properly clean up the memory, not direct kfree().

According to the kobject API documentation, kobject_init_and_add()
calls kobject_init() internally. If the subsequent kobject_add()
fails, the kobject has still been initialized and must be cleaned up
via the reference count mechanism (kobject_put), not direct kfree().

Direct kfree() leaves the kobject's internal state (including the
reference count and kset membership) uncleaned, which can cause:
 - Memory leaks of kobject internal structures
 - Potential use-after-free if there are pending references
 - Inconsistent state with the rest of the error handling code

This fix matches the pattern used elsewhere in the kernel and in the
same function (err_put label) which correctly uses kobject_put().

Fixes: 3485b88390b0 ("mm: thp: introduce multi-size THP sysfs interface")
Signed-off-by: Hongling Zeng <zenghongling@xxxxxxxxxx>
Suggested-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>

---
 Change in v2:
 - Use goto err_put instead of kobject_put() + goto err for consistency
 - Add suggested
---
 mm/huge_memory.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2bccb0a53a0a..589f7bf1f19d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -818,10 +818,8 @@ static struct thpsize *thpsize_create(int order, struct kobject *parent)
 
 	ret = kobject_init_and_add(&thpsize->kobj, &thpsize_ktype, parent,
 				   "hugepages-%lukB", size);
-	if (ret) {
-		kfree(thpsize);
-		goto err;
-	}
+	if (ret)
+		goto err_put;
 
 
 	ret = sysfs_add_group(&thpsize->kobj, &any_ctrl_attr_grp);
-- 
2.25.1