CVE-2024-35993

mm: turn folio_test_hugetlb into a PageType

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. [willy@infradead.org: update vmcoreinfo]

N/A

CVSS

Severity:

EPSS 0.12%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/2431b5f2650dfc47ce782d1ca7b02d6b3916976f
https://git.kernel.org/stable/c/9fdcc5b6359dfdaa52a55033bf50e2cedd66eb32
https://git.kernel.org/stable/c/d99e3140a4d33e26066183ff727d8f02f56bec64

Frequently Asked Questions

What is the severity of CVE-2024-35993?: CVE-2024-35993 has not yet been assigned a CVSS score.
How to fix CVE-2024-35993?: To fix CVE-2024-35993, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2024-35993 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2024-35993 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2024-35993?: CVE-2024-35993 affects Linux Linux, Linux Linux.

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