Medium [CVE-2026-72176] put stats for scheme_add_dirs internal error

In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: put stats for scheme_add_dirs() internal error damon_sysfs_scheme_add_dirs() setup the tried_regions directory after the stats directory setup is completed.

When the tried_regions directory setup is failed, the setup function ensures the reference for the tried regions directory is released. Hence the error path should put references on setup succeeded directory objects, starting from the stats directory.

However, the error path is putting the tried_regions directory instead of the stats directory. As a direct result, the stats directory object is leaked.

Worse yet, if the tried_regions directory setup failed from the initial allocation, the scheme->tried_regions field remains uninitialized. The following kobject_put(&scheme->tried_regions->kobj) call in the error path will dereference the uninitialized memory.

The setup failures should not be common. But once it happens, the consequence is quite bad.

The issue was discovered [1] by Sashiko. A flaw was found in the Linux kernel's mm/damon/sysfs-schemes component, which could lead to a denial of service or system instability.

This vulnerability is caused by an incorrect error handling path in the damon_sysfs_scheme_add_dirs() function, resulting in a resource leak and the dereference of uninitialized memory.