CVE-2021-47491 (GCVE-0-2021-47491)

Vulnerability from cvelistv5 – Published: 2024-05-22 08:19 – Updated: 2025-05-04 07:12
VLAI?
Title
mm: khugepaged: skip huge page collapse for special files
Summary
In the Linux kernel, the following vulnerability has been resolved: mm: khugepaged: skip huge page collapse for special files The read-only THP for filesystems will collapse THP for files opened readonly and mapped with VM_EXEC. The intended usecase is to avoid TLB misses for large text segments. But it doesn't restrict the file types so a THP could be collapsed for a non-regular file, for example, block device, if it is opened readonly and mapped with EXEC permission. This may cause bugs, like [1] and [2]. This is definitely not the intended usecase, so just collapse THP for regular files in order to close the attack surface. [shy828301@gmail.com: fix vm_file check [3]]
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0 , < 6d67b2a73b8e3a079c355bab3c1aef7d85a044b8 (git)
Affected: 99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0 , < 5fcb6fce74ffa614d964667110cf1a516c48c6d9 (git)
Affected: 99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0 , < a4aeaa06d45e90f9b279f0b09de84bd00006e733 (git)
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    Linux Linux Affected: 5.4
Unaffected: 0 , < 5.4 (semver)
Unaffected: 5.10.78 , ≤ 5.10.* (semver)
Unaffected: 5.14.16 , ≤ 5.14.* (semver)
Unaffected: 5.15 , ≤ * (original_commit_for_fix)
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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