CVE-2023-52939

A flaw was found in the memory management subsystem in the Linux kernel. A NULL pointer dereference can be triggered due to an improper check of the memory cgroup value, resulting in a system crash and a denial of service.

In the Linux kernel, the following vulnerability has been resolved: mm: memcg: fix NULL pointer in mem_cgroup_track_foreign_dirty_slowpath() As commit 18365225f044 ("hwpoison, memcg: forcibly uncharge LRU pages"), hwpoison will forcibly uncharg a LRU hwpoisoned page, the folio_memcg could be NULl, then, mem_cgroup_track_foreign_dirty_slowpath() could occurs a NULL pointer dereference, let's do not record the foreign writebacks for folio memcg is null in mem_cgroup_track_foreign_dirty() to fix it.