CVE-2024-35993 mm: turn folio_test_hugetlb into a PageType
A race condition in the Linux kernel memory management can cause a null pointer dereference and system crash during memory compaction when debug options are enabled.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-35993?
CVE-2024-35993 is a high-severity vulnerability in Linux kernel, published on 20 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
mm: turn folio_test_hugetlb into a PageType
The current folio_test_hugetlb() can be fooled by a concurrent folio split into returning true for a folio which has never belonged to hugetlbfs. This can't happen if the caller holds a refcount on it, but we have a few places (memory-failure, compaction, procfs) which do not and should not take a speculative reference.
Since hugetlb pages do not use individual page mapcounts (they are always fully mapped and use the entire_mapcount field to record the number of mappings), the PageType field is available now that page_mapcount() ignores the value in this field.
In compaction and with CONFIG_DEBUG_VM enabled, the current implementation can result in an oops, as reported by Luis. This happens since 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") effectively added some VM_BUG_ON() checks in the PageHuge() testing path.
[[email protected]: update vmcoreinfo]
Which versions are affected by CVE-2024-35993?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-35993?
Apply the vendor's patch.
Is CVE-2024-35993 being exploited?
There is no known exploitation of CVE-2024-35993 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-35993, DEBIAN-CVE-2024-35993, GHSA-q9r2-5479-5hm7, UBUNTU-CVE-2024-35993.